ROCHESTER — A former top executive at the Mayo Clinic was secretly hired by a competitor but continued to work for the medical practice and research group so he could steal trade secrets, the Rochester-based clinic alleged in a lawsuit.

Mayo filed suit Tuesday against Dr. Franklin R. Cockerill III, the president and CEO of Mayo Medical Labs for eight years, alleging misappropriation of trade secrets and breach of contract.

Cockerill told his department in July that he was going to retire and move to Nebraska to help his 85-year-old mother run her business, according to the complaint. But he went to New Jersey in October to work as the vice president and chief laboratory officer of Quest Diagnostics Inc., a multibillion-dollar public company that’s a competitor of Mayo Medical Labs, the complaint said.

According to Mayo Clinic, Cockerill had been communicating via email with Quest about a potential job since February. He participated in a March phone interview with the company and traveled to New England for a phone interview in May, when Cockerill said he needed to take some time off to help his mother with a business problem, according to Mayo.

He accepted his new position at Quest in June, the complaint said, but continued to work at Mayo Medical Labs for several more months. Mayo contents Cockerill attended confidential meetings while it was unaware that he would soon be a Quest employee. Cockerill was present for the discussion of issues that could cause irrevocable damage if the information reached Quest, according to Mayo Clinic.

The former Mayo executive discussed business strategies with Quest CEO Stephen Rusckowski through a series of emails in August, the lawsuit states.

Mayo Clinic also said Cockerill took at least seven clinic-owned USB memory drives with him when he left. At least four of those drives were used to “download information from Dr. Cockerill’s computer in the days before . (he) started working for Quest,” the lawsuit reads.

Mayo Medical Labs and Quest Diagnostics Inc. compete for millions of dollars in medical contracts.

Court records don’t indicate an attorney for Cockerill. Quest declined to comment Thursday.