A MASKED man armed with a hammer threatened the owners of a Keighley convenience store in an attempted robbery yesterday.

The broad daylight offence, which took place at 5.15pm, in Staveley Road, has been linked by police to three other incidents in Bradford between yesterday afternoon and this morning.

They want to identify and speak to a man in connection with all four crimes.

Describing the Keighley incident, a police spokesman said: "The suspect demanded money, threatened the owners with a hammer, but they were able to activate the alarm and he fled empty handed."

The police say the Keighley incident was the second of the four attempted robberies.

The first occurred at 1.05pm yesterday at a Bookmakers on Allerton Road. The manager was threatened by a suspect with a hammer outside the premises but was able to fight him off and escaped with minor bruises.

Just before 9pm yesterday, the suspect entered a convenience store on Thornton Road demanding money and brandishing a small claw hammer.

The owner struggled with the suspect and was repeatedly struck with the hammer.

The suspect then smashed his way through a Perspex screen and out of the shop, during which time his face was uncovered and captured on CCTV. No property was stolen and the man escaped on foot down Middlebrook Way.

The fourth incident took place at 6.45am this morning, when a woman resident of a pub on Girlington Road was approached by a man as she came out of a side door.

She managed to lock the door and get away and the suspect was seen running towards Thornton Road.

Detective inspector Neil Benstead, of Bradford CID, said: "At this stage we believe the incidents are linked. It is still possible that what happened this morning is not connected, however we are investigating every possibility.

"On each occasion the victims were left shaken and, in two cases, they have physical injuries as a result of what occurred.

"Hopefully someone will recognise this man from the CCTV footage or from the description provided by the victims and witnesses.

"We urge anyone who might have information about these attempted robberies or who was in the area at the times when they were committed, to call us on 101 or ring Crimestoppers anonymously on 0800 555111."

A composite description of the suspect has portrayed him as being a dark skinned man, aged 20 to 35 years, of slim build, between five feet seven inches and six feet tall, clean shaven and wearing a dark jacket and gloves.