TORONTO -- One of Ontario's highest-ranking police officers is threatening to sue Premier Doug Ford accusing him of defamation.

In a notice of intent to sue filed last month, lawyers for Ontario Provincial Police Deputy Commissioner Brad Blair allege that Ford damaged the officer's reputation when he accused him of breaking the Police Services Act by speaking out against the hiring of a Ford family friend for the force's top job.

Blair's lawyer Julian Falconer further alleges that Ford's comments were meant to intimidate his client, who publicly criticized Toronto police superintendent Ron Taverner's appointment as OPP commissioner.

"Specifically, it is alleged that you intentionally, deliberately, and maliciously made statements you knew or ought to have known to be false," Falconer said in a letter to Ford.

Falconer said Ford told media that Blair had allegedly violated the act, when there is no evidence the veteran officer did so at any time during his career.

"The preparation, distribution and publication of these defamatory words have caused extensive harm to Deputy Commissioner Blair's professional and personal reputation, as well as other damages to be specified at a later date," Falconer said.

In December, Blair said OPP officers had expressed concerns the selection process which resulted in Taverner's appointment was unfair and could raise doubts about the police service's independence.

Blair, who was also in the running for the commissioner's job, also suggested that Taverner's appointment be delayed until an investigation could be conducted by the province's ombudsman.

After the ombudsman declined to investigate, Blair launched a legal challenge in an attempt to force the watchdog to probe the hiring. Ontario's Divisional Court is expected to hear the case in April.

The court documents filed in the case also contain more details about Blair's allegations that Ford's chief of staff asked the OPP to purchase a "larger camper type vehicle" and have it modified to the specifications of the premier's office, with the costs associated with the vehicle "kept off the books."

The documents show the cost to taxpayers for the van remodel would be over $50,000, not including the cost of the vehicle itself. The custom features were to include a 32-inch television with Blu-Ray player, a mini-fridge, black leather captain's chairs and a reclining leather sofa bench, the documents said.

A spokesman for Ford said Monday that the premier asked the OPP to look into obtaining a "cost-effective used van" for him to work and travel in across the province.

"The emails sent to the OPP from a member of the premier's office staff are not an official procurement of a van, instead they are a cost estimate and reveal an effort to minimize expense," Simon Jefferies said in an email.

Blair's lawyers said they filed the notice of intent to sue for defamation after the government failed to respond to four letters seeking to clarify if Blair was under a Police Services Act investigation.

Jefferies denied Ford's statements were a reprisal against Blair.

"Mr. Blair is an unsuccessful candidate, and still appears to be clearly upset that he did not get the job," he said, adding that the premier would respond to any legal proceedings through his counsel if necessary.

NDP Leader Andrea Horwath called Ford's actions "shameful" and said his comments were an attempt to intimidate Blair.

"I think it's another indicator of this government's desire to put a chill on anybody that's going to speak out against them," she said.