The family of a 62-year-old trucking executive who mysteriously disappeared from her Wyoming home last year is offering a $250,000 reward for any information on her whereabouts.

Kristi Richardson's home in Casper was undisturbed when police arrived on Oct. 7, 2014 -- the front door deadbolted, both cars in the garage and the recently-widowed executive's purse where she always left it. While investigators and her family are convinced she met with foul play, there is no evidence of murder and no arrests have been made in the case.

"We are no closer today to recovering her than we were a year ago," Capt. Steve Freel of the Casper Police Department told FoxNews.com. "We still don’t have that tip."

"It’s like someone just left and didn’t take anything with them," Freel said, noting that detectives believe Richardson is dead. 

Richardson, the longtime owner of a trucking business in Casper, was last seen on Oct. 6, 2014, when she drove to her daughter's home -- on the same block -- to drop off a birthday card and visit her grandchildren. Phone records show that later that day, at 7:45 p.m., Richardson took a routine phone call from one of her drivers. The next call to Richardson's phone, at 11 p.m. and from a vendor that does business with Richardson Trucking, went unanswered.

When Richardson did not show up for work the next morning, her 41-year-old daughter, Amber Fazio, entered her home using a spare garage door opener. No one was home, and the house was undisturbed, according to Fazio. In addition to the purse, which held Richardson's ID and $800 cash, Fazio said her mother's cellphone was in the home.

"Please reflect on your human compassion, your heart, your conscience and come forward with any information that will help us bring our mother and grandmother home."

- Tracy Richardson, son of Kristi Richardson

A source close to the investigation said detectives are eyeing a former employee of Richardson's who wanted to have a romantic relationship with the woman before and also after her husband died in 2013. Richardson turned him down, the source said. The man, a former truck driver who has not been named, denied being in Richardson's neighborhood on the night of Oct. 6 but has "unexplained gaps in his story," according to the source.

Freel declined to speak about the man in question, saying only that there are a "handful" of persons of interest in the case and "no one has been ruled out."

Freel said he is looking at several possibilities, including one that the grandmother of five might have been targeted by a current or former employee of Richardson Trucking, a well-known trucking company she owned with her late husband since 1979. Freel said detectives are also investigating employees at competing companies in the investigation, noting that a booming oil and gas industry has brought an influx of people and new businesses to the area.

"Do I think that it's someone from outside of this area? Not really, but maybe -- like a disgruntled customer or someone from a rival company that may not be in this area," said Freel.

On Monday -- the one-year anniversary of the disappearance -- Richardson's family announced they were increasing the reward from $50,000 to $250,000 for any information leading to her whereabouts. The hefty reward is being supported by family as well as people in the trucking, oil and gas industries and the local business community.

"Please reflect on your human compassion, your heart, your conscience and come forward with any information that will help us bring our mother and grandmother home," Richardson's son, Tracy, said at a press conference Monday.

In an interview with FoxNews.com Wednesday, Richardson described his mother as "super dedicated" to her business and said she would never miss a phone call. He also said she would never allow a stranger into her home.

"Someone out there knows something," Richardson said. 

"If it's money that is going to get the answer, that's great by us. We don’t care about the money," he said. "We just want to find out what happened to our mom."  

Anyone with information on the case is urged to call investigators at 307-235-8202. 

Cristina Corbin is a New York-based reporter for FoxNews.com. Follow her on Twitter @CristinaCorbin.