BOULDER, Colo. -- Authorities are still trying to identify an armed intruder killed by a Boulder-area couple when he burst into their home earlier this month.

Investigators say the man was in his 20s or 30s and was white or Hispanic. They have collected DNA and dental samples in case someone comes forward to say he is a relative.

An autopsy revealed a peculiar tattoo on the man that investigators hope someone will recognize.

Authorities say the man died after being beaten by a baseball bat and stabbed with his own knife. They told officers that he forced his way into the house after the woman answered the door. That's when the two fought back.

Authorities say the couple were defending themselves and will not be charged in the man's death.