The man at the centre of the dramatic search for a three-year-old boy who disappeared from his home in a small British Columbia town has an extensive criminal record, including a conviction for sexual assault that dates back to the 1980s.

Kienan Hebert disappeared from his home in Sparwood some time between Tuesday night and Wednesday morning, setting off a frantic search of the surrounding area and then an Amber Alert, which was issued Wednesday evening.

The Amber Alert named Randall Hopley, 46, as a "suspect," and the RCMP have said they're hoping to speak to him about the boy's disappearance. He is believed to be driving a brown 1987 Toyota Camry with the licence plate 098RAL.

Hopley, who police say has no known connection to the boy, has a criminal record that covers most of his adult life and is currently on probation.

In the mid-1980s, Hopley was convicted of sexual assault and sentenced to two years in federal prison, the National Parole Board confirmed. Hopley finished serving that term in September 1987, but the board didn't have any further information because its records are destroyed after 10 years.

Provincial court records show numerous convictions for Randall Peter Hopley, born in 1965.

This past June, he was sentenced to two months in jail and two months of probation after he was convicted of assault. The assault occurred in April of this year in Sparwood, court records indicate.

In November 2007, he was charged with break-and-enter, unlawful confinement and attempted abduction, confirmed Crown spokesman Neil MacKenzie.

Hopley pleaded guilty to the break-and-enter and was sentenced to 18 months in jail, but the unlawful confinement and attempted abduction were stayed over concerns about evidence, said MacKenzie.

Hopley was also convicted in 2006 for a break-and-enter in Sparwood, for which he received a conditional sentence of nine months, according to court records.

In 2003, he received a one-year conditional sentence for theft under $5,000, and in 2002 he was handed a three-month conditional sentence after he was convicted of break-and-enter.

Hopley also has several convictions for breaching conditions.

Amber Alert messages were broadcast throughout B.C. as far away as Vancouver, where display screens on transit buses and the city's SkyTrain system urged the public to tune into local radio stations.

Kienan was last seen Tuesday evening when he was put to bed in the family home. He was described by police as a red-haired Caucasian boy who was last seen wearing a blue pair of Scooby Doo boxer shorts.

RCMP Cpl. Dan Moskaluk declined to say what led police to issue an Amber Alert targeting Hopley.

"I don't have the full background on Mr. Hopley, certainly more information will become available as we can release it," Moskaluk told reporters.

"Putting it bluntly, amongst us we do have people that have previously been involved in criminal activity in a variety of criminal offences. ... Some of them become quite good citizens and partake in our communities and integrate back, but some don't."

Kienan's father, Paul Hebert, said he was holding out hope that his son will soon be back at home safe and sound.

"Everyone's on hand, the professionals are doing what they can do, and we just have faith that Kienan will be coming back home and safe," he told reporters Thursday morning.

"We have eight kids. Our six-year-old has had three heart surgeries, and now we deal with a kidnapped child -- to me, kidnapped; he also could be lost, we won't speculate on what's going on. But we hope for the best for Kienan's safety and that he'll be home safe."

Hebert described his son as a "great kid."

"He's super happy all the time," said Hebert. "If you see him, you'll think he's a cute little button. He's just a happy kid."

Dale Fedorek, who was born and raised in Sparwood, said he remembers Hopley hanging around when he was in high school.

"He was quite a bit older. I just remember him as the dirty, creepy guy who always rode his bike around. In a small town, you always remember the goofy characters," said Fedorek.

"You'd just seem him riding his bike around. Every day he'd be in the mall. I know he had those problems in the past a couple of years ago and that's the last I've seen of him."

Fedorek said he's not sure if Hopley held a job other than picking bottles. He said Hopley's family isn't from Sparwood, though he wasn't sure when he came to town.

Fedorek's mother Debbie said the boy's disappearance has shocked Sparwood residents.

"It's very rough on the community and things like this don't happen here. But the town has changed lots," she said.

"Nothing like this happened here while I was growing up."

Kienan vanished from an upscale neighbourhood with manicured lawns, not far from a local golf course.

The family's two-storey home was surrounded by yellow police tape. Two cruisers were parked in front and a handful of uniformed RCMP officers were waiting outside.

In addition to the Amber Alert, police were continuing a ground search in town and the surrounding woods of the Elk Valley, which lies in the shadows of the Rocky Mountains near the Alberta-B.C. boundary.

Immediately after Kienan was reported missing, search-and-rescue officials then went into action. A police dog unit and RCMP helicopter were called in to conduct a search of the ground.

Police said about 200 people were involved in the initial ground search on Wednesday, and that number had grown on Thursday.

Moskaluk has said Kienan has a history of sleepwalking, but he didn't speculate about whether that is related to the boy's disappearance. Kienan's sleepwalking has never taken him outside the home, said Moskaluk.

Internet users were taking to Facebook to wish the family well.

"I will be leaving my light on tonight in hopes he finds his way home safe," wrote one user on a Facebook page titled "Pray for the safe return of Kienan Hebert," which had more than 6,000 members.

"Stay strong little man. If only you knew how many people are looking for you."