A sex predator with a previous conviction for attacking a woman has been found guilty of dragging another woman into an alleyway and raping her after threatening that he had a gun.

Melbourne Thompson, 41, was already on the sex offenders register when he targeted the woman as she walked to work in Catford, south-east London.

His criminal history stretches back more than two decades. In 2005, he was convicted of indecently assaulting a woman in 2003.

Police said the latest attack bore similarities to his previous offending.

Now detectives are investigating whether he could be responsible for other incidents. No further offences have been confirmed in the information released.

Thompson, of Eltham, was convicted of rape and robbery at the Old Bailey on October 9. He remains in custody and is due to be sentenced on December 4.

The attack exposed the danger he poses to women: he followed a stranger, punched her in the head and used the threat of a gun to terrorise her.

When she tried to shout for help, he covered her mouth and dragged her into an alley off Minard Road, where he raped her. He then stole her phone from her jacket pocket.

The woman sought help from a bus driver, who alerted police at about 6.55am on April 12. She was taken to a specialist sexual assault referral centre and continues to receive support from specialist officers.

Investigators traced her stolen phone to an area around four minutes from Thompson’s home, approximately half an hour’s walk from the scene.

His previous conviction also proved crucial to identifying him. An officer who had monitored Thompson following that conviction recognised him in CCTV footage.

He was arrested on April 28 and appeared at Bromley Magistrates’ Court the following day, when he was remanded in custody.

More than 20 years after his earlier conviction, Thompson has been convicted of another violent sexual attack on a woman. As he awaits sentence, police are examining whether there are further victims.