I've read through this thread a few times now, and it seemed to me that there were so many misconceptions and assumptions and suppositions, particularly from the "shoot first" crowd, that I had to do some serious research to get to the heart of it. So, that said, let's be about it....
In Nebraska's opening post, he quotes most of the relevent sections of the new law:
QUOTE
"A person is justified in using deadly force against another to protect his property to the degree he reasonably believes the force is immediately necessary to prevent the other's imminent commission of arson, burglary, robbery, theft during the nighttime or criminal mischief during the nighttime, and he reasonably believes that the property cannot be protected by any other means."
"A person is justified in using deadly force against another to prevent the other who is fleeing after committing burglary, robbery, or theft during the nighttime, from escaping with the property and he reasonable believes that the property cannot be recovered by any other means; or, the use of force other than deadly force to protect or recover the property would expose him or another to a substantial risk of death or serious bodily injury. (Nighttime is defined as the period 30 minutes after sunset until 30 minutes before sunrise.)"
To that I would only add this:
QUOTE
PROTECTION OF THIRD PERSON'S PROPERTY. A person is justified in using force or deadly force against another to protect land or tangible, movable property of a third person if, under the circumstances as he reasonably believes them to be, the person would be justified under Section 9.41 or 9.42 in using force or deadly force to protect his own land or property
and:
(1) the person reasonably believes the unlawful interference constitutes attempted or consummated theft of or criminal mischief to the property;
and(2) the person reasonably believes that:
(A) the third person has requested his protection of the land or property in writing;
(

he has a legal or contractual duty to protect the third person's land or property; or
the third person whose land or property he deadly force to protect is the person's spouse, parent, or child, resides with the person, or is under the person's care.
Now, looking at all of this, it's quite clear that Mr. Horn is, legally at least, in the wrong. Why?
First, his defense under the first two parts, fails out-right, in that this crime did not take place at night. The 911 call was placed at about 2PM. And additionally, during the call, as you'll be able to see from the transcript, Horn says he can't believe that this is happening in broad daylight.
Second, while the first two sections say that the person can use such force if he believes that there is no other way to recover or protect the property, that statement is still predicated on the fact that the crime has to happen during the nighttime.
Lastly, as is also noted in the call transcript, Mr. Horn did not know these neighbors well at all. I think he would be hard pressed to show written prior authorization to protect their property, he was not employed by them contractually to protect them, and they most assuredly were not immediate family members, nor were they under Mr. Horns care.
Now, let's turn our attention to the transcript of the call, up until the shooting:
QUOTE
Horn: Not my address, next door. Uh, I've got a shotgun. You want me to go stop them?
Dispatcher: Nope, don't do that. Ain't no property worth shootin' somebody over, OK?
Horn Gives a decription of the two suspects- then--
Horn: Hurry up and catch these guys, will you? I'm not gonna let 'em go. I gotta be honest with you, I'm not, I'm not gonna let 'em go. I'm not gonna let 'em get away with this s---. I'm not gonna hang up, but I'm not gonna put up with this stuff, man. This is just ridiculous.
Dispatcher: Yes sir, it is.
Horn: Broad daylight - I don't know if they're armed or not. I know they got a crowbar, because that's what they broke the window with.
Dispatcher: Which window did they go in through?
Horn: The side window by where the fence is, so nobody could see them. Right hand side, looking from the front. Man, this is scary. I can't believe this is happening in this neighborhood.
Dispatcher: Can you see anything at all?
Horn: No, I can just see where they went into the house. I can't see in the house.
Dispatcher: I understand that, but you can see where they entered in?
Horn: Yes.
Dispatcher: So they might slip out the same way, or can you see the front of the house?
Horn: I can't see the front of the house, but if I'm going out there, I'm taking my shotgun, I swear to God.
Dispatcher: No-
Horn: I'm not gonna let 'em get away with it. I'm not takin a chance on getting killed over this, OK? I'm gonna shoot, I'm gonna shoot.
Dispatcher: No. stay in the house. Don't go out there, OK? I know what you're feelin', but it's not worth shooting sombody over, OK?
Horn: I don't want to, but if I go out there to see what the hell is going on, what choice am I gonna have?
Dispatcher: No, I don't want you to go out there. I just asked if you could see anything out there.
Horn: I can see a little bit of the driveway, but I can't see the front.
Dispatcher: Can you see anything at the front of the house, like a vehicle they came in or anything?
Horn: No
Dispatcher: Let me know if you can see anything at all from where you're at. Don't go outside, OK? ...Mr Horn, you still there?
Horn: I'm here. I can't see anything out the front. I can't tell if they stole anything and are gettin' away or not.
Dispatcher: OK. That's alright.
Horn: Well, over there - I would assume - I hope not.
Dispatcher: Ok. I mean, you know your neighbors?
Horn: No I really don't know these neighbors. I know the neighbors on the other side really well. I can assure you if it had been their house, I'd have already done something. Cause I know them really well, and, you know.
Dispatcher: Mr Horn? I want you to listen to me very carefully, OK?
Horn: OK.
Dispatcher: I got officers comin' out there. I don't want you to go outside of that house. And I don't want you to have that gun in your hand, when those officers are poking around over there.
Horn: I understand that sir, but you know I have a right to protect myself and you understand that too.
Dispatcher: Yes Sir.
Horn: And the law's been changed in this country since September the first, and you know it and I know it. I have a right to protect myself. And a shotgun is a legal weapon, it's not an illegal weapon.
Dispatcher: No, it's not. I'm not sayin' that. I'm not wanting you to, you know--
Horn: Hes coming out the window right now, I gotta go, buddy. Im sorry, but hes coming out the window.
Dispatcher: Dont, dont dont go out the door. Mr. Horn? Mr. Horn?
Horn: Damnit, they just stole something. Im going after them, Im sorry.
Dispatcher: Dont go outside.
Horn: I aint letting them get away with this s--t. They stole something. They got a bag of something.
Dispatcher: Dont go outside the house.
Horn: Im doing this!
Dispatcher: Mr. Horn, do not go outside the house.
Horn: Im sorry. This aint right, buddy!
Dispatcher: Youre going to get yourself shot if you go outside that house with a gun, I dont care what you think.
Horn: You want to make a bet? I'll kill 'em!
Dispatcher: OK? Stay in the house.
Horn: Theyre getting away!
Dispatcher: Thats all right. Propertys not worth killing someone over, OK?
Horn: [curses]
Dispatcher: Dont go out the house. Dont be shooting nobody. I know youre (PO'd) and youre frustrated, but dont do it.
Horn: They got a bag of loot.
Dispatcher: OK. How big is the bag ... which way are they going?
Horn: Im going outside. Ill find out.
Dispatcher: I dont want you going outside, Mr. Horn.
Horn: Well, here it goes, buddy. You hear the shotgun clicking and Im going.
Dispatcher: Dont go outside.
Horn: [yelling] Move, youre dead!
[Sound of shots being fired]
Now, as we have discovered, Horn shot both men in the back, while he maintains that they were "lunging" at him. Question: How do you lunge at someone with your back turned to them?
In addition, I looked up the address listed in the transcript (which I deliberately withheld here, but is easy enough to find). These are basically "zero lot-line homes". That means there is very little space between the homes, about enough for a side door from the garage to swing completely open without hitting the fence, on each side of the fence.
In other words, at the time Mr. Horn goes from his side window, to the front door, after seeing the suspects leave the neighbors house, they were already onto his property, because of how little room there was. From the police report released, it's apparent that at the time he yelled, "Move, you're dead!", they saw him at about the same time and began moving away from him. The police officer that arrived on the scene just as they were leaving and Mr Horn came out of his door, confirms this.
The officer had to duck, because Mr Horn swung his shotgun on one suspect who was running toward the street, and fired in the general direction of where the officer's car was, hitting and killing the first suspect. Then, Mr Horn swung back towards the neighbor's house, where the second suspect had already almost cleared the yard, and fired again, killing the second man.
In my opinion, Mr Horn, at the very least should be charged with a number of crimes. Failure to follow the lawful directions of a representative of the police department (the dispatcher). Reckless endangerment, for firing his weapon without clearing fields of fire, and voluntary manslaughter.
Mr Horn on more than one occasion in the 911 call, made it plain he was looking to go out and force a confrontation, so he could shoot something (or someone). While Mr Horn was inside his home, he was in no imminent danger. He put himself in the position of being in danger, after being repeatedly told not to, and on review of the 911 call its obvious he knew the repercussions. Its clear he knew if he went outside he was going to shoot somebody, and rationalized his actions under the guise of the law that had recently been passed. He said he had the right to protect himself. But he wasnt protecting himself, he pursued the conflict. He was the one who escalated the situation.
Now, this being Texas, even if he should be charged by the Grand Jury, I think it highly unlikely that he'll be convicted of the deaths of these two criminals. But he should be. Because no man under our system of justice is entitles to be cop, judge, jury, and executioner all at once. Not over property, at any rate. I can't think of a single man-made thing that's worth someone's life.