A businessman on the brink of retirement was among those critically injured as explosions ripped through crowds at the finish line of the Boston Marathon.
John Odom from Torrance, California, father-in-law of former LA Galaxy goalkeeper Matt Reis, was cheering on his daughter Nicole Reis when the first of two bombs went off.
It exploded just 20 feet away from where Mr Odom was with other family members watching the race.
He suffered a severed artery in his leg and, despite his daughter and others rushing to his aid to apply tourniquets, lost so much blood that his heart stopped twice.
'His legs were blown apart ... his heart took a big hit because of the loss of blood,' said his brother-in-law Doug Nicol.
Bomb experts have revealed that the makeshift bombs which exploded in central Boston on Monday afternoon were like 'home-made claymores' packed with shrapnel to cause horrific injuries to those in range.
Last night Mr Odom's condition had stabilised enough that surgeons at the Boston Medical Centre were able to operate on his shredded legs, a procedure family members said which went well.
'We feel that he is now on a long road to recovery,' Reis posted on his Facebook page last night, according to the Contra Costa Times. 'We have to take it day by day.'
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Mr Odom, who is believed to be in his 60s, is chairman of Murray Co, a successful mechanical plumbing contractor in the South Bay.
His son Donny was with him at the time of the explosion. Soon after, he told U.S. television: 'They took my dad to the Boston Medical Centre. I helped carry him to the ambulance.
'He couldn’t walk, and he was really cold - we tried to keep talking to him to keep him alert.
'It's just unbelievable that this would happen at an event like this.'
Bloody scenes: The immediate aftermath of the explosions. Mr Odom (not pictured) suffered a severed artery in his leg and lost so much blood that he had to be resuscitated twice
Mr Odom's brother-in-law, Doug Nicol, who also works for Murray Co, said the invitation to the businessman's retirement party only arrived the morning before he was injured in the bomb attacks.
'John is the nicest guy you'll ever meet,' said Mr Nicol. 'He puts everything in front of himself, there isn't anything he wouldn't do for anybody.
'It's just insane this happened four weeks before he was going to retire.'