Jacqueline Avant Awake During Fatal Shooting, Surprised Intruder

Jacqueline Avant's family believes she was awake at home when an intruder shot and killed her, as Clarence was nearby in the couple's bedroom ... TMZ has learned.

Sources close to the situation tell us Clarence was asleep during the break-in last week at their Trousdale Estates home, but his wife was already up just after 2 AM -- as she typically is -- in another room.

We're told she and the suspect unexpectedly came face-to-face ... the family believes they startled each other and that's when he opened fire.

Our sources tell us security was patrolling the front of the house and the suspect appears to have entered from the side yard.

We're told a guard heard a gunshot from inside, raced over and then the suspect fired at him too ... before fleeing the scene.

As we reported ... cops took a man named Aariel Maynor into custody about an hour after the crime, and say he's the guy responsible for killing Jacqueline. They allege he was attempting yet another burglary in the Hollywood Hills, where he apparently shot himself in the foot.

The police say he's the sole perpetrator in the Avant killing, and they also say he used an AR-15 style weapon.

Maynor has since been charged with murder, attempted murder, felony with a firearm as well as 2 counts of residential burglary with a person present ... all in connection to the Avant shooting. We're told he's scheduled to have surgery on his foot Wednesday, so he won't be arraigned until after that.