Translink has launched a "full investigation" into the mugging of a pensioner at a train halt in Co Antrim after a witness claimed the victim was put off a train by a member of staff.

Police said a man aged in his eighties was assaulted just before 5pm on Sunday after exiting a train at the Derriaghy Halt in Lisburn.

A witness, who took to social media following the robbery, said the elderly victim and his alleged attackers had been put off the train by a member of Translink staff.

Writing on social media, the witness asked: "Did anyone witness an incident yesterday on the 4.11pm train from Great Victoria Street to Portadown?

"When he confronted them the conductor instructed them all to exit the train at Derriaghy station, where they assaulted him and took the contents of his wallet".

The post led to criticism of Translink.

One woman wrote: "My goodness , shocking behaviour" another added: "Appalling. I hope it's being investigated by Translink".

A spokeswoman for Translink said: "The safety of our passengers and staff is our top priority.

"A full investigation is under way following this incident and we are assisting the PSNI with their enquiries, including provision of CCTV," she said.

Police have appealed for witnesses to come forward.