Donald Trump has retweeted a picture of a convicted murderer currently serving three life sentences, apparently believing it to show a “Vietnam vet”.

Trump regularly retweets messages of support for his presidential campaign and has dedicated a large portion of his Twitter feed to posts praising him for attacking Senator John McCain’s status as a Vietnam war hero in recent days.

The Republican hopeful was lambasted for dismissing McCain because he was captured as a prisoner of war but has refused to apologise or retract his comments.

Trump apparently shared a tweet on Monday evening containing an image of Jeffrey MacDonald, a former US army officer and medical doctor who was found guilty of killing his pregnant wife and their two daughters in 1970.

The image featured a picture of MacDonald in military uniform, underneath the caption: “My bad ass Vietnam vet dad has balls too which is why he’s voting Trump!”

The error was quickly highlighted by other Twitter users but remained live on his account over seven hours later. It has since been deleted.

This is not the first time Trump has inadvertently tweeted a picture of a murderer. In September, the business tycoon threatened to sue a Twitter user who duped him into sharing a picture of the serial killers Fred and Rose West by pretending it was a picture of their late parents.