Detectives are investigating whether the death of a pensioner, who was savagely attacked by a gang outside his Bradford home almost two years ago, was murder.

Keith Alder was beaten with baseball bats and kicked unconscious in the brutal, unprovoked attack in October 2011, which led him to have both legs amputated above the knee.

He died following a stroke aged 68 at Bradford Royal Infirmary on August 7 and now police are probing whether there is a direct link between the attack and his death following a post-mortem examination by a Home Office pathologist.

Last night a West Yorkshire Police spokesman said: “A police investigation is under way to establish whether there is a link between the assault in October 2011 and the subsequent death.”

Mr Alder, a roofer, had only just retired when he was left for dead by the gang outside his then home in Great Horton.

He was on his way home from the Fat Pot club at about 11.15pm, when a gang started shouting at him in Southfield Lane.

He tried to run, but only got as far as his driveway in Sowden Street before he was attacked.

The father-of-three had been looking forward to spending his retirement pursuing his love of fishing, but instead endured a string of medical problems as a result of the attack.

He spent almost eight months in hospital and suffered head injuries and kidney damage, which led to pneumonia.

Emergency surgery was needed to remove most of his bowel after scans revealed it had rotted, and he was then put into an induced coma for a week. He contracted an MRSA infection and gangrene cost him both legs above the knee. He also lost six-and-a-half stone.

Despite having had his legs amputated, Mr Alder’s family said he tried to live as full a life as possible, going on holiday to Butlins and getting his driving licence back. His family believed he was on the mend.

Mr Alder’s wife, Kath, and his eldest son, Paul, smiled and laughed as they told of their memories of a much-loved and popular man.

Speaking at Mr and Mrs Alder’s bungalow in Queensbury, surrounded by flowers and cards, Paul told of his dad’s sense of humour and love of fishing.

Paul said that sense of humour didn’t diminish even after he had lost his legs. “We were at a garden party,” said Paul. “He said he had to go inside because his feet were cold.”

A talented match fisherman, Mr Alder tried, unsuccessfully, to get his three sons interested in fishing. However, Paul fondly remembered fishing and camping trips he enjoyed with his dad.

Mrs Alder joked: “He was off fishing every weekend - I was a fishing widow. He paid for me to go off on holiday because he felt guilty”

“Our marriage was absolutely brilliant. We had three lovely boys, no worries with money, a lovely house, good pension, no mortgage – we were very lucky. We had everything to live for.”

Paul told how he worked alongside his dad, a roofer, for seven years. “He put the roof on Meadowhall in Sheffield,” said Paul. Mr Alder worked as a roofer until his retirement aged 65.

Two days before his stroke, the couple attended her sister’s grandson’s wedding in Elland. Paul said his dad drove there and back, and Mrs Alder added: “We had a great night.”

The couple had lived in Great Horton for more than 40 years up until Mr Alder was attacked.

Stanley Shoesmith, who knew Mr Alder for 50 years, yesterday spoke of how the attack changed his friend and paid tribute to him. He believes the injuries he suffered did contribute to his death.

“It’s disgusting what has happened, he was attacked for no reason,” said Mr Shoesmith, 74, of Wibsey, who has feared going into Bradford since the attack. Not a quieter man walked the earth. He helped everybody and this has brought his death on.

In April 2012, Bartolomej Makula was jailed for 15 years after pleading guilty to causing Mr Alder grievous bodily harm with intent and possession of a baseball bat.

In February this year, Makula’s nephew, Ladislav Balaz, was convicted by a jury of grievous bodily harm with intent. He was jailed for 16 years.