DETROIT — A jailed adult entertainment consultant convicted of tax evasion was able to manage his business for more than 18 months in Michigan using a laptop computer in his cell and jail telephones, authorities said.

Francis Sharrak, 44, of Farmington Hills was serving as his own lawyer at the time and asked for the laptop to prepare arguments for his federal court sentencing in April, but he wasn’t supposed to have the computer, Detroit Free Press reported (www.on.freep.com/104mcJj ) Tuesday.

“Now, I am the first one ever to have a computer in the history of this jail,” Sharrak said during a recorded phone call from jail in January 2011. Federal prosecutors have asked the judge to consider a transcript of the call when sentencing Sharrak.

Sharrak was held at the Wayne County Jail in Detroit in a cell for high-profile inmates. Sheriff’s officials that run the jail acknowledge that Sharrak had the computer, but called it an isolated case. The case involved an employee who has since been fired for other reasons, Undersheriff Daniel Pfannes said.

“We were misled initially by an employee who said there was a court order giving him access to a laptop computer,” Pfannes said.

Officials later learned there wasn’t a court order, Pfannes said, and the department also changed policies to avoid a repeat in the future. On March 8, the sheriff’s department seized Sharrak’s computer. Sharrak filed a motion to get it back, saying he’d had it since August 2010 and that it was essential to his defense.

A federal judge denied the request.

Sharrak currently is in federal prison. He wasn’t charged for any actions in jail, but prosecutors asked a judge to consider them at sentencing.

“Through his past conduct as proven at trial, and his apparently continuing conduct of the same nature, even while confined, defendant has shown that he simply refuses to abide by laws, rules, restrictions and directives imposed upon him,” Assistant U.S. Attorney Carl Gilmer-Hill wrote in a sentencing memorandum.

Between 1997 and 2001, federal prosecutors said Sharrak made $3.7 million from his business operating and promoting adult websites and from being a consultant to strip clubs. He also was convicted of failing to file tax returns. His sentence included six years in prison and $4.2 million in restitution.