Earlier attack also by rapist?

A serial rapist may have attacked four women in Hamilton, police say.

It was today revealed they were investigating a complaint of a sexual attack that happened before three other rapes which they believed could be linked to one attacker.

Detectives had also reactivated other unresolved historic sex complaints to see if there were links to their investigation, dubbed Operation Phil.

Last week police announced they were hunting a serial rapist after attacks on women in the city in April, May and July.

While not directly linking all four attacks, Hamilton police are not ruling it out, saying the complaint has "similarities to the current investigation".

No details of the latest complaint have been revealed.

People had already come forward with a "vast amount" of information for CIB staff to work through, since the operation was made public last week, police said.

An identikit picture of the man suspected of the rapes was released last week.

CIB Detective Senior Sergeant Chris Page said the man was described as caucasian with fair hair, aged between 18 and 30. He had convinced the women to get into his car on the pretence of help or a ride home.

Police say women need to be careful about their safety when out drinking.

Police have set up a freephone number for people with information on any of the cases, 0800 TOCATCH (0800 862 282).