Peter Wetzler was charged last year with killing Debra Campbell in early 1984.

His lawyer argued the case against him was weak, and today the office of public prosecutions agreed, dropping the murder charge levelled at him.

Peter Wetzler
Peter Wetzler was charged last year with killing Debra Campbell in early 1984. (Nine)

“There was a great weight off my shoulders. It’s all still sinking in,” Wetzler told 9News.

“I knew he was innocent,” Wetzler’s wife Sandy said.

“So to see this happen to him was so unfair.”

Wetzler was engaged to the 21-year-old Campbell in 1984.

They were in the air force together when she disappeared in February of that year.

He dropped Campbell at her apartment in the Melbourne suburb of Windsor the day she disappeared.

The two had an argument earlier in the day, something Wetzler doesn’t deny, but he maintains he was never violent.

Debra Campbell vanished from her Victoria home in 1984 - nearly 40 years later- police are asking the public for help to finally close this suspected cold case.
Debra Campbell vanished from her Victoria home in 1984. (Victoria Police)

“I thought she was going to come back, and when she didn’t I thought, ‘Something’s happened to her’,” he said.

Wetzler spent five weeks in jail before being granted bail and spent tens of thousands of dollars on his legal defence.

He’s now fighting for Victoria Police to pay his costs.