Orange County investigators shared their frustrations in trying to solve a deadly home invasion in which 50-year-old John Brennan was shot and killed as he tried to protect his wife after five men broke into his Bridlewood home in July.

Detectives are trying to get as much information as possible out to the public, so the case doesn't go cold, and they’ve released a neighbor’s surveillance video that recorded a group hours before the shooting.

The surveillance footage appears to show a group of people walking in front of the home hours before the break-in.

“It's sketchy, it's not clear, but you can see about four to five figures walking past the home around midnight, about four hours before the murder occurred,” said Jane Watrel of the Orange County Sheriff’s Office.

During the home invasion, Brennan tried to defend his wife, stepping between her and a gun. He was shot and killed in his living room while his teenage son hid in a bedroom.

 “He went down defending my mom,” the son later said.

In another piece of surveillance footage, the killers can be seen running from the home and speeding away in a car.

Despite that video, however, authorities have not been able to identify any suspects.

Detectives think, fear may be keeping witnesses from coming forward. Anyone with information is asked to contact CrimeLine, which is completely anonymous.