(CNN) -- Police in Escambia County, Florida, questioned a man in connection with the July slayings of a couple known for adopting special-needs children, a spokeswoman said Thursday night.
Henry "Cab" Tice, a used car dealer, has been arrested on suspicion of grand theft, police say.
Henry "Cab" Tice, a used car dealer, was arrested on suspicion of grand theft, said Escambia County Sheriff David Morgan. Police said they believe Tice wrote a series of bad checks to one of the victims, Byrd Billings, Morgan said.
Tice, 61, faces one count of grand theft of over $10,000 related to financial dealings with Billings' Worldco Financial Services, according to a sheriff's statement. The charge is related to a criminal investigation launched in May 2008, the statement said.
"We are pleased that the investigation is continuing as to the May 2008 complaint filed by Bud Billings related to the theft of the cars," a statement from the Billings family said. "We have faith that Sheriff Morgan will be diligent in determining whether there is any connection between Cab Tice and the murders."
Eight suspects face charges in the murder of Billings and his wife, Melanie, who were shot to death during a home invasion robbery in Beulah, Florida, on July 9. Seven men are charged with first-degree murder and a woman is charged with being an accessory after the fact. State Attorney Bill Eddins said Thursday a grand jury would be convened in the case August 11.
Tice owed Billings money, and Billings was attempting to recover the debt, according to civil court and corporate records.
Asked whether Tice's charges are related to the slayings, Morgan said, "Not at this time." But he said he will release further information about Tice's "dealings in the car business as it relates to the Mexican Mafia."
The sheriff described those dealings as under-the-table cash sales of cars along the border to be resold in Mexico. Tice had borrowed up to $50,000 at one time from the Mexican Mafia, and was in debt to them, Morgan told reporters. He declined comment on whether police believe the Mexican Mafia had ties to the Billings slayings. Tice remains a "person of interest" in the killings, he said.
Tice went to the sheriff's department on his own volition to be questioned in connection with the slayings, said sheriff's spokeswoman Melissa Aiken.
A source with knowledge of the investigation told CNN in July that prosecutors believe there were two motives in the killings -- robbery and a contracted hit. The source said the state attorney's office is working under the belief that most of the suspects in the case thought they were robbing the Billingses, but that Leonard Gonzalez Jr., who authorities have described as the organizer of the crime, and other yet-unnamed suspects were plotting a hit on the couple. The source was not sure of the exact motive behind the hit.
A small safe containing prescription medication, family documents and some jewelry was taken from the home, and later found in the backyard of a woman who said she was a friend of Gonzalez and is now facing the accessory charge. Two sources familiar with the investigation have told CNN a second safe at the home contained at least $100,000.
The Billingses had adopted 13 children, and each had two biological children. Police have said nine of the children were home at the time of the assault, and one managed to flee and seek help from a neighbor.
Gonzalez, his father, Leonard Gonzalez Sr., and two other suspects in the case are set for arraignment August 13. Two other suspects are set for arraignment Friday.
CNN's Ross Levitt, Aaron Cooper and Carolina Sanchez contributed to this report.