A man has been jailed for at least 26 years for the “cold-blooded murder” of his ex-wife and the burying of her body in his garden.

Alireza Askari, 42, admitted killing Paria Veisi, 37, at the property they previously shared in Penylan, Cardiff, in April last year.

Veisi had separated from her husband and moved out of the house earlier that month, Cardiff crown court heard.

Police found her body buried in a “makeshift grave” in the rear garden, concealed by patio slabs, soil and newly planted flowers.

On Friday, Justice Stacey sentenced Askari to life imprisonment with a minimum term of 26 years for the “cold-blooded murder” of Veisi.

William Hughes KC, prosecuting, said Askari had murdered his ex-wife in the conservatory of the house at about 4.30pm on 12 April before attempting to destroy any evidence with the help of his aunt Maryam Delavary, 48.

The court previously heard Askari and Veisi moved to the UK from Iran in 2010 and had married, but were living separately at the time of the murder.

Analysis of Askari’s phone found he had been texting a woman in Iran, believed to be his girlfriend, before the killing.

In one message, he told the woman: “I’m planning for them to kill her in Iran.”

On the day of the attack, Askari bought the suspected murder weapon, a set of kitchen knives, from a supermarket before returning home.

Hughes said that after burying Veisi in a makeshift grave,

Askari rang Delavary in London before making another trip to the supermarket, where he bought bleach, compost and plants.

Delavary travelled to Cardiff in a taxi “to assist in the covering up of Paria’s murder”, Hughes said.

A friend of Veisi contacted South Wales police the day after the murder, raising concerns that she was “being kept against her will by her ex-husband”, and a missing person investigation was launched.

On 15 April, Askari was arrested while driving from Birmingham to Cardiff. Canisters containing caustic soda were found inside the vehicle.

Hughes said: “These chemicals … were to be used in the destruction of Paria’s remains.”

Veisi’s body was found during a search of the property. She had four stab wounds, and injuries to her chest and neck.

Addressing Askari, Justice Stacey said: “She was in the prime of her life, her death has destroyed her family’s happiness, as you knew it would.

“You subjected Paria to abuse at home and [she] was fearful of you; Paria confided to her friends how scared she was of you.

“You recruited your aunt … You did everything in your power to cover up the murder, to destroy evidence and to hinder the South Wales police investigation.”

He said Askari killed Veisi because she had left him and wanted a divorce.

“Your hypocrisy was staggering – at the same time you wanted [Paria] out of the way so you could take up with your girlfriend in Iran.”

Askari, of Penylan, Cardiff, had previously pleaded guilty to murder and preventing the lawful and decent burial of a body. A further charge of assault occasioning actual bodily harm was ordered to lie on file.

Delavary, of White City estate, west London, previously pleaded guilty to perverting the course of justice.

She was sentenced to five years and six months in prison.