Joel Richards, 20, was left at Birmingham's City Hospital on Sunday where he died from his injuries.
A 17-year-old boy was arrested on suspicion of murder at a service station on the M40 on Monday evening.
West Midlands Police also stopped a car on the motorway near Oxford and arrested three men and a woman on suspicion of assisting an offender.
Supt Tom Chisholm said:  "This continues to be a fast paced inquiry and we have made five arrests over the bank holiday weekend.
"However, our work is not done and we continue to investigate the circumstances that led to this young man's death.
"We will still continue to liaise with Joel's family and our thoughts remain with them as they continue to come to terms with their loss."

Southampton's second 13-mile event was held on Sunday and attracted more than 6,000 runners.
Race director Chris Rees said there was "definitely a demand" for a 26.2-mile (42km) run at next year's event and one could be formally announced by the autumn.
More than 500 people responded to the suggestion on social media, he added.
Southampton City Council has said it cannot "offer any comment at this early stage", but added it was "delighted" by the recent successes of the half marathon.
The inaugural Southampton half-marathon was held last April, along a route that passes many of the city's landmarks, including the Bargate, St Mary's Stadium and Itchen Bridge.
Organisers said most people who had responded to the suggestion of a full marathon favoured a separate 26-mile route, rather than the idea of running the 13-mile route twice.
Mr Rees said: "This weekend showed how much the city embraces and enjoys running so it would be great to have a marathon in the city - it just has to be done right.
"We've got a couple of ideas and proposals and we want to work with the council, runners and community groups and residents to make sure they are all backing the event."

UK government figures showed Scotland generated 4,590 gigawatt hours (GWh) of renewable energy in the first three months of 2012.
This was an increase of 1,435 GWh on the first quarter of 2011.
Scotland is aiming to generate the equivalent of 100% of its electricity needs from renewables by 2020.
The UK Department of Energy and Climate Change also issued revised statistics for 2011 which showed that renewable electricity generation in Scotland was 13,735 GWh in 2011, an increase of 44.3% from 2010 and up 97.3% from 2006.
The Scottish government said that, assuming gross consumption in 2011 was similar to 2010, about 35% of Scotland's electricity needs came from renewables in 2011, beating its interim target of 31%.
Scottish Energy Minister Fergus Ewing said the figures showed the country was making good progress towards the 2020 target.
He added: "The increase of 45.5% in renewable output in quarter one 2012 compared to quarter one 2011 is particularly encouraging when you consider that 2011 saw the highest output from renewable energy to date.
"Scotland has astounding renewable energy potential, and the Scottish government is committed to ensuring every community in Scotland benefits from the opportunities of renewable energy.
"Scotland is a genuine world leader in green energy and our targets reflect the scale of our natural resources, the strength of our energy capabilities and the value we place on creating new, sustainable industries."
Jenny Hogan, director of policy at Scottish Renewables, said the figures demonstrated that renewable energy was becoming an "ever important of our energy mix".
She added: "Each time you boil a kettle in your home, more and more of that electricity will have been generated from a renewable source such as a wind farm.
"Not only does the renewables industry now employ more than 11,000 people in Scotland, it's helping to reduce our carbon emissions, tackle climate change and insulate us from volatility in the gas market which has been responsible for the major hikes in energy bills over the last few years."
WWF Scotland's head of policy Dr Dan Barlow added: "To ensure Scotland remains on track to a fully renewable future we need to see continued and rapid deployment of all forms of renewables alongside investment in energy efficiency.
"Such a path will help create jobs, reduce pollution and protect households from volatile fossil fuel prices."
Labour Shadow Energy Minister Tom Greatrex said: "Any increase in renewable generation is welcome. The investment needed to make Scotland's renewables potential a reality is supported by consumers across the whole of Britain, not just in Scotland."
Five people have been arrested after a man left at a hospital died of stab wounds.
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Organisers of the Southampton half marathon have said they would like to introduce a full marathon to the city.
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Scotland's renewable energy output increased by 45% in the first quarter of this year, compared with the same period last year.