HOUSTON -

Derrel Sims, a larger than life Texan living near Houston, is an alien hunter.

"I suspect they're living on a massive craft," said Sims.

Sims walks around in a cowboy hat and coat in the middle of the summer.

"They seem to love fear," he added.

Sims claims to be the world's leading expert on alien abductions, whose fascination began as a child.

"My first interaction with these entities was at age 4 in Midland, Texas," Sims said.

After nearly four decades tracking extraterrestrial events, Sims is now a Hollywood star, appearing in a cable TV show called "Uncovering Aliens."

"So I use my skills as an investigator, a former cop, a combat cop in the military and a private investigator," said Sims.

These days he works with a team to investigate reports of alien activity --looking for proof.

"You usually find markings on these people, cuts, bruises, scratches, lumps, bumps, and things that don't make sense," he said.

So what does an alien look like?

Sims says he's seen one face to face.

"The entity was actually right outside my tent. It stood no more than three feet tall and had a head," he said. "Then there's another being that looks like a reptile. There is a human like being that stands six foot."

Yeah, it sounds crazy but Sims says it's serious and no one is immune. He claims one in every four people is abducted by aliens and the victims come from all walks of life.

"You would be shocked, stunned and amazed to find out who's on my list of clients," Sims said. "There are scientists, intelligence people, NASA scientists and others who are abductees. It doesn't make a difference. You can be a genius."

So what puts you most at risk for an alien event? Sims says his research points to a pattern.

Many of the people being taken, that turn out to be abductees, are Native American Indians, Irish, Celtic.

If a relative was abducted, you are more likely to be a victim too.

Sims believes the phenomenon runs in families.

"Go talk to your family privately," Sims said. "You're going to be stunned with what you're going to hear... because if it happened to you, it'll be in your family lineage."

This online questionnaire will help you figure out if you've been taken.

Still not a believer?

Sims says he doesn't care, "Let's just say I would like to capture one of them."

His hunt continues.

"I still have a lot of work to do," said Sims. "I'm an investigator, finding the evidence and doing something with it is my business."