A man who beat his estranged wife's new boyfriend to death has been jailed for life.
Suren Sivananthan, 32, was found dead near the Co-op in St Leger Drive, Great Linford, Milton Keynes, on 21 January.
A jury convicted Gnanachandran Balachandran, 38, from Milton Keynes, and a 17-year-old from Croydon of murder.
Balachandran was told he must serve at least 18 years in prison. The teenager must serve at least 11 years.
A third defendant, Prashanth Thevarasa, 24, from Milton Keynes, was sentenced to 10 years in prison for causing grievous bodily harm with intent.
The court heard Mr Sivananthan, who was on a visit from Canada, had been staying with Balachandran's estranged wife in Milton Keynes.
Sri Lankan Balachandran snatched his "rival" from a Milton Keynes shopping centre and kept him captive for 12 hours before beating him to death.
Sentencing him at Luton Crown Court, Judge Richard Foster told him: "You were unable to accept the reality that your marriage was over and it is clear that you felt humiliated by the situation."
David Bentley QC, defending Balachandran, from The Fleet in Springfield, Milton Keynes, said there had been no evidence to suggest the attack was "pre-planned".
Thevarasa, of Farrier Place, Downs Barn, Milton Keynes, was acquitted of murder and found guilty of the lesser charge.
He acted with "a lack of maturity", the court heard.
The badly beaten body of Mr Sivananthan was found by a parade of shops in Great Linford at about 04:00 GMT on 21 January.
He had received 39 separate injuries to his head and neck, plus bruises on his arms, legs, back and chest.
A post mortem showed he died from sustained blunt force trauma to the head, which resulted in a brain injury.