There is a lot we don't know about this particular incident. There has been more and more coming out in the local media about it and about the officer that fired his weapon.
The first reports of the story said the pen in his hand was silver. I don't know if that has been confirmed or if it has been corrected. A silver pen like a Parker could easily at a distance be mistaken for a knife blade or a an ice pick.
Conventional ballistic type soft body armor does not protect against ice picks or knives like a correctional "stab resistant" vest does. So a guy with a pointy thing is a very real threat to an officer wearing a standard issue type vest.
The call as dispatched made no mention of weapons, and did not identify the location as a group home of any kind , just a as a disturbance at a residence.
We don't know if the responding officers even work that beat regularly so we don't know if they were familiar with the location and its residents.
We don't know if the officers arrived at the same time or if the first officer got himself in a jam and the second officer walked in the door to find the first officer cornered by a guy in a wheel chair with a shiny pointy thing.
We do know that the shooter has previously shot and killed someone that was stabbing someone and was commended for saving that victim's life.
A spokesman for the union was on KHOU last night and said in response to a community activist who said they should have used a Taser that except under "ideal circumstances" Tasers are not used against subjects armed with what is believed to be a deadly weapon.
To ensure "full transparency" the chief has asked the FBI to come in and investigate the incident.