The shooter in a murder-suicide Tuesday just off the University of Maryland campus worked briefly for the campus police.
A university police spokesman said Wednesday that Dayvon Maurice Green worked as a police auxiliary officer for about two weeks in August and September. He did not carry a badge or a gun, but had a police radio that would allow him to summon a sworn officer if he spotted trouble.
Spokesman Marc Limansky said Green was fired after he twice failed to show up for work.
Police say Green shot two roommates, one fatally, and then killed himself early Tuesday after setting a series of small fires in around the home he rented.
Green's family told police that he had been suffering from mental illness for at least a year.