Darren Joseph Casey (28), now with an address at Claragh Hill Grange in Kilrea, was sentenced to a total of 18 months, nine in custody and the remaining nine on licence, when he appeared at Antrim Crown Court.
The court was told that on May 5, 2012, Mr McKeown had died after jumping into the river at Kilrea, after being pursued by Casey, whom he had met in order to collect steroids hidden in the area.
An altercation took place between the two men during which Mr McKeown struck Casey before running off in the direction of the river, followed by Casey.
The deceased jumped into the water and initially appeared to swim before going under the water.
A group of canoeists using the river observed the two men running towards the river, while they also observed Casey jump in to try to save Mr McKeown before eventually leaving the scene.
The court was told that Casey and his father had attended Coleraine PSNI station that evening, during which the defendant was in a “distressed” state.
Sentencing Casey, Judge Gordon Kerr said the defendant had “over-reacted” to being slapped by Mr McKeown who, he said, had run off while “trying to escape further assault”.
Describing the incident as “a highly exceptional case”, the judge said that any injuries Mr McKeown had sustained in the altercation had been “medically insignificant”.
He described Casey’s level of culpability as “low”, stating there was a “lack of direct connection” between Casey’s actions and the cause of Mr McKeown’s death by drowning.
Judge Kerr sentenced Casey to 15 months’ imprisonment for this offence and also ordered a previously imposed suspended sentence of three months to be activated to run consecutively. He ordered half the total sentence to be served in custody, with the remainder on licence.