Marissa Aldrich drowning: Robert McWhir jailed for murder
A man who drowned his on-off partner in a drainage pond has been jailed for a minimum of 18 years for her murder.
Robert McWhir, 25, forced Marissa Aldrich's head underwater after the pair "argued and wrestled".
He claimed to have a phobia of water and said he had "tried to clamber over" Ms Aldrich, 29, when the pair fell into the pond in St Neots last December.
Sentencing McWhir, Judge David Farrell said he had killed Ms Aldrich "out of jealousy and possessiveness".
Cambridge Crown Court heard the couple had left a party at a flat at 02:10 GMT on 22 December and started arguing during while walking along Loves Way.
Jurors were told the pair were "punching and slapping each other", before they fell down a short bank into the pond.
When a friend called McWhir, the defendant was heard to say "I'm killing her, I'm killing her", the court heard.
Forensic pathologist Dr Virginia Fitzpatrick-Swallow said silt was found embedded in Ms Aldrich's teeth, airways and stomach.
Her lungs were heavy with abnormal levels of fluid, which the court heard were "classic features associated with drowning".
Bruises on Ms Aldrich's body were consistent with restraint, the jury was told.
Judge Farrell said the killing was a "senseless, drunken and violent act" and he was "satisfied it was [McWhir's] intention to kill her".
In a statement, Ms Aldrich's mother Gemma Aldrich said her daughter's death had "torn apart" the family.
She said: "Every night I close my eyes I picture Marissa with fear in her eyes. This does not go away - I imagine it never will."
McWhir was also given a concurrent three-year term for attempting to pervert the course of justice.