Prosecutors dropped their charges Wednesday against a woman who was accused of killing her ailing husband after police found surgical gear, bloody bed sheets and what appeared to be human tissue during a search of the couple's suburban Detroit home.

Laura Johnson, 46, was charged with second-degree murder, manslaughter and practicing medicine without a license in the death last week of 47-year-old Lloyd Johnson.

Prosecutors asked for the charges to be dropped after an autopsy determined Lloyd Johnson died of complications from an open wound on his lower back sustained years ago when he was pierced by a boat oar.

"We're relieved it's over," defense lawyer John Williams said outside court Wednesday.

Laura Johnson left the courtroom dabbing her eyes and declined to talk to reporters.

Lloyd Johnson weighed 413 pounds and had other health problems, including cardiovascular disease, diabetes and cirrhosis, Oakland County medical examiner L.J. Dragovic said Tuesday.

Oakland County assistant prosecutor Paul Walton said the investigation is ongoing. He said in court there appeared to be some conflicting opinions between the medical examiner and medical personnel at Botsford Hospital, where Lloyd Johnson was treated after reportedly suffering a heart attack Sept. 20. He died two days later.

"The medical examiner has issued media statements that apparently contradict several of the medical records as well as evidence that was collected at the scene by police," Walton said.

Walton said toxicology reports as well as other medical records will be turned over to independent experts for their opinion on the cause of death.

According to Walton, Lloyd Johnson told medical personnel at the hospital before he died that his wife does home wound care and that it is an "issue of conflict right now between family members."

After the hearing, Walton addressed criticism that the prosecutor's office was too quick to charge Laura Johnson in her husband's death. He said the charges were based on information they had at the time, including police reports and medical records from Botsford Hospital. Authorities also were concerned about getting her away from her two school-aged sons, Walton said.