The home is appears to be owned by Linda Shaw, a woman Maldonado's family knows as his girlfriend.
Maldonado was shot and killed just before midnight by another man.
"Neighbors heard some screams from a female," said Jim Amormino, a spokesman with the Orange County Sheriff's Department. "The female did have a 51-year-old male house guest staying with her at the time."
Investigators said Maldonado entered the home through an unlocked sliding door.
"He went into the bedroom, some kind of confrontation occurred where the 51-year-old male shot and killed Mr. Maldonado," Amormino said.
Authorities have seized the gun used in the shooting but have not released details on who owns the gun or the name of the man who shot Maldonado. He has not been arrested, officials said.
Detectives said the relationship between Shaw and the house guest is unclear.
Neighbor Jerry Vitta was awake reading in bed and heard noise coming from next door.
"I heard a little bit of a commotion," Vitta said. "It wasn't very loud by any means, and all of a sudden after the commotion I heard pop pop pop, three shots."
Vitta said Maldonado was cordial to him in the past and has known Shaw, her ex-husband and their two children for about six years.
"I know Linda pretty well and she's a nice woman," Vitta said. "I feel very sorry for the family and everybody associated. It's just heartbreaking, for both families."
Maldonado is the owner of a bail bonds company.
According to his daughter, Megan, Maldonado and Shaw were headed for marriage.
Megan Maldonado said her father loved the beach, working out and his kids.
She said she and her brothers have lost an amazing person and father.