The father of a three-month-old baby who died after being given lethal doses of a heroin substitute has been found guilty of manslaughter.
Nathan Grain denied the manslaughter of his three-month-old son
Nathan Grain, 34, of Paterson Place, Shepshed, Leicestershire, was found guilty of killing his son Luke by giving him methadone and diazepam.
Grain had told Leicester Crown Court he gave the drugs to his baby son to stop him crying.
A jury took one hour to convict him. He will be sentenced on 7 June.
Remanding Grain in custody on Thursday, Judge Michael Pert QC, said: "It's inevitably going to be prison and a substantial prison sentence.
"You have been convicted by this jury. I will sentence when I've got all the reports."
After Luke died on 15 January 2006, toxicology reports found high levels of methadone and diazepam in his blood.
At the time, Mr Grain was on a methadone recovery programme for a heroin addiction.
In police interviews after the baby's death, Mr Grain said he may have passed the drugs on to his son by transferring the baby's dummy from his mouth.
When the amounts found in Luke's blood were deemed too high for this explanation, Mr Grain said the dose must have been administered by someone else.
He said a friend and the baby's grandmother had been at the house in Shepshed at the time the drugs were given but DNA checks suggested Grain gave his son the drugs by using a cup.
Luke's cause of death was recorded as an overdose of methadone and diazepam, a lethal combination for a child, experts said.