Not sure why the officers said he lunged. Maybe they really perceived that. Maybe he moved his hand with the knife as if he was going to come at them. The family stated he wanted the police to shoot him and that he was Schiz/Bipolar and off his meds. If they out and out lied - then they deserve whatever punishment is coming.
No sure about Dallas PD. But in many agency deadly force policies, if an officer commands a person to drop a weapon, and that person fails to comply, deadly force is both legal and within policy. It’s not like the movies where the officer says, “drop it!” 20 times. If the person doesn’t comply then there is no reason to believe telling them over and over will do the trick. There’s nothing gained in giving the bad guy time to figure out how to best attack or build up the nerve to attack.
If someone is armed with a knife and there no obstacle between you and the suspect, your an idiot to deploy a taser. Sometimes they work great, sometimes not. The second officer clearly kicks something away from the suspect as they approach him. Don’t know all the details so I won’t venture into if they acted properly or not. If the suspect isn’t actively moving on you, there are options in most PD’s for less lethal if the suspect refuses to disarm himself. Stunbag shotguns, 40mm etc… But this takes time, that’s the thing about being a Leo… Seconds to make a decision, years to deal with it afterwards. If your alive.
A person with a knife is definitely considered a deadly threat encounter. A taser is not really a viable option in most situations even with deadly cover. 1) You still have to get fairly close (much closer than I want to be). 2) Say you do get close enough to use a taser and the suspect charges you? I’m not betting my life on hitting a now moving target with two taser probes. Now you have fellow officers using deadly force in your direction. And we all know how poorly some cops shoot.
Language is definitely something to consider. Not a whole lot you can do about that. I think it’s pretty standard that in any country you’re in if cops point guns at you to lay down.
The officer should not have lied on his report. That’s just plain stupid in today’s age of surveillance cameras and cell phones. Whether he should have waited longer and tried to talk him down, I don’t know, I wasn’t there. Could they have contained him? Maybe. Do you wait until he starts to run in the direction of a citizen’s home and then shoot? Tough call to make.