A third suspect has been arrested by detectives investigating the murder of a shopkeeper who was stabbed to death at his store in Birmingham.

West Midlands Police said the 29-year-old man was detained this morning in connection with Saturday's stabbing at a shop in Kingstanding.

Officers were already questioning a man aged 26 and a 25-year-old woman who were arrested on Sunday on suspicion of murder.

The 48-year-old victim, named in reports as Suppiah Tharmaseelan, was attacked at the Select Convenience Store in College Road, Kingstanding, during a suspected robbery and was pronounced dead at the scene.

It is believed the victim's teenage daughter witnessed the stabbing on the store's CCTV system as she sat in the family flat above the shop.

Abid Hussain, owner of a takeaway store in the same street as the shop, said the victim was a father-of-three, originally from India, who "always had a smile on his face".

Mr Hussain, who runs the Kingstanding branch of Dixie Chicken, said: "He was a very sensitive man, a family man. He had three children, two sons and a daughter, and a wife and they all helped out in the shop."

The businessman added: "I spoke to a relative of his wife outside the shop this morning and he told me the daughter was watching the CCTV upstairs and she saw it all happening.

"I heard she was the one who called police. I can't imagine how she must feel, and his sons."

Detectives are appealing for information from anyone who saw a group of four men running away from the shop.

Acting Superintendent Richard Youds, from North Birmingham Police, said: "We would like to speak to anyone who saw four men running from the store or anyone who has information that could lead to their identity.

"Extra officers remain at the scene and the local area patrolling and speaking with local residents. These increased patrols will continue to offer reassurance as we try to establish the circumstances around the events of Saturday night."

Anyone with information about the murder is asked to contact West Midlands Force CID, Operation Skyblue, on 0345 113 5000 or via the independent charity Crimestoppers on 0800 555 111.