The father of one of the victims of the Lockerbie bombing has criticised plans by the US Department of Justice to make an announcement on the anniversary of the attack.

Rev John Mosey, the father of 19-year-old victim Helga Mosey, received an email from the Lockerbie appeal team at Scotland’s Crown Office, which forwarded an invitation from the US Department of Justice to the families of victims.

The invitation said an “important public announcement and update regarding the investigation” from US attorney general William Barr would be livestreamed on its website on Monday.

Monday is the 32nd anniversary of the bombing above the Dumfries and Galloway town.

Why exactly, when the attorney general is about to leave office, has he waited 32 years to bring charges?

US media have reported in recent days that the Justice Department expects to unseal charges in connection with the attack, with the Wall Street Journal and New York Times naming Abu Agila Mas’ud as the suspect.

In a reply to the invitation, Rev Mosey said he considered the “timing and particularly the choice of this specific day, which is special to many of us, to be bizarre, disrespectful, insensitive and extremely ill considered”.

He added: “Why exactly, when the Attorney General is about to leave office, has he waited 32 years to bring charges?”

The bombing of Pan Am flight 103, travelling from London to New York on December 21 1988, killed 270 people in Britain’s largest terrorist atrocity.

Former Libyan intelligence officer Abdelbaset al-Megrahi, who was found guilty in 2001 of mass murder and jailed for life with a minimum term of 27 years, was the only person convicted of the attack.

He was released from prison in 2009 on compassionate grounds and died in Libya in 2012.

Lawyer Aamer Anwar is representing the family of al-Megrahi in their appeal against his conviction and also acts for the family of some of the victims.

He said: “The families I represent are horrified at the intrusion on their grief, on the day that they wish to remember their loved ones.

“The fact that the outgoing attorney general William Barr thinks it is appropriate to invite families to watch his ‘grandstanding’ at a press conference is deeply disrespectful to the families and victims.

“Many of the families will refuse to do so and suspect the motivation of choosing to prosecute 32 years after the bombing.”