Persons of interest photos released in mysterious case of couple ambushed, 'executed' at gated community

— -- Authorities in Houston released surveillance images of two persons of interest this morning as they hunt for clues in a couple's mysterious double killing in their gated community.

Investigators believe Bao and Jenny Lam, both 61, came home around 8:40 p.m. Thursday "and were ambushed by suspects as they parked their car in the garage," the Harris County Sheriff's Office said.

The victims' son, who went to check on his parents Saturday night after not hearing from them since Thursday, called police from the home, the sheriff's office said. When deputies went inside, authorities said they found the Lams bound and shot to death.

"They were executed," Harris County Sheriff Ed Gonzalez told reporters this morning.

The sheriff's office said surveillance video from the entry gate at the couple's subdivision shows two suspects arriving at about 8:20 p.m. Thursday in a 2007 to 2014 black Lincoln Navigator. The suspect parked near the gate and then crawled under the gate and into the subdivison, according to the sheriff's office. The suspect in the passenger seat was described by authorities as "unusually tall," possibly 6-foot-4 or taller.

Authorities said the suspects "ambushed the Lams inside their garage and forced them into their residence, where they were bound, robbed, and murdered." Their hands and feet were bound, officials said.

After ambushing the Lams, the suspects allegedly fled in the Lams' car before returning and going into the house a few hours later, authorities said. Over the course of those few days, the suspects likely went back into the house several times, the sheriff's office said.

The house appeared to be ransacked with firearms and other valuables were missing, the sheriff's office said.

There could be up to four suspects, the sheriff's office added.

At this morning's news conference, the victims' daughter, Michelle Lam, begged "the public to please help us."

"We miss them so much," she said. "They were just going home from having dinner."

Son Richard Lam, a military officer, called his parents his "personal superheroes."

He said his parents immigrated to the United States in the 1970s and worked several jobs at once.

"They just made sure we had every opportunity to realize our dreams," he said. They later built successful businesses, the sheriff said.

Richard Lam said his father always wanted to be a military officer and often spoke how great the American military is.

"They were truly amazing people. They give their time and money to the community. My dad, if anybody asked him for help, he would not hesitate to give them a hand," he said, while his mother had "sage advice" for "every chapter" in their lives.

"Two men broke into their home last week killed them in cold blood," he continued. "We just need your help."