John Kinsella was shot by the cyclist on Saturday morning, and Merseyside Police believe the attacker was wearing a hi-vis jacket at the time.
The 53-year-old, who lived locally, died at the scene in Rainhill Stoops near St Helens.
Kinsella had previously been involved in a £41,000 robbery in Grantham, Lincolnshire in 2006, where thousands of pounds worth of detergents, crisps and Easter eggs were stolen.
He was captured in Amsterdam in 2009 and started a 10-year jail term in Lincoln prison.
During his trial, the jury heard how Mr Kinsella had stopped a gangster terrorising Steven Gerrard, who played for Liverpool at the time.
The court was told that the star’s father, Paul Gerrard, had asked Kinsella to intervene so the footballer would no longer be “threats from the Liverpool underworld” – spearheaded by “The Psycho” – would stop.
In a letter that was read out in court, Gerrard Sr wrote: “Steven and I have total respect for John for what he did for us.”
Following Saturday’s shooting, Detective Superintendent Lee Turner said: “The offender is reported to have been around 6ft tall, of slim build and wearing dark clothing and a hi-vis jacket.
“He is also believed to have been riding a mountain bike.”
Mr Turner urged anyone who used the slip road between 6.30am and 7.30am on Saturday, particularly those with dashcam footage, to get in touch with police.
The news comes as a spate of violent crimes are reported across the country this bank holiday.
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Monday’s national newspaper front pages
A 17-year-old boy was shot dead in Southwark, south London on Saturday evening.
On Sunday morning, a 20-year-old man died after being stabbed in Liverpool city centre.