Poland’s former honorary consul in Monaco Wojciech Janowski is being formally investigated over the murder of his wealthy mother-in-law, heiress Helene Pastor, French prosecutors say.

Wojciech Janowski, 64, had “recognized his involvement” in the killing of Helene Pastor, Marseille prosecutor Brice Robin said earlier.

Helene Pastor, from one of Monaco’s richest families, was shot along with her driver as she left hospital in Nice.

Wojciech Janowski’s wife Sylvia was also detained but released without charge.

Seven other suspects from a total of 23 detained in the French cities of Nice, Marseille and Rennes were placed under investigation on Friday.

Among them was the Pastor family sports instructor, Pascal Dauriac.

Poland’s former honorary consul in Monaco Wojciech Janowski is being formally investigated over the murder of his mother-in-law Helene Pastor

Both Helene Pastor, 77, and her chauffeur Mohammed Darwich, 64, were deadly wounded when a man with a sawn-off shotgun ambushed their car on May 6 as it was leaving the hospital where she had been visiting her son.

The prosecution alleges that Wojciech Janowski paid hit men to carry out the killing.

Brice Robin said Wojciech Janowski’s motive was to “lay his hands on the inheritance” of his common-law wife.

Wojciech Janowski spent 250,000 euros ($340,000) to contract the killing, the prosecutor said.

He announced earlier that Wojciech Janowski’s bank account had seen suspicious financial flows which needed explanation.

Poland dismissed Wojciech Janowski, a Cambridge-educated businessman, from his post as honorary consul after his arrest because of the “loss of his good reputation and trustworthiness”.

Two suspects in the shooting were identified after police studied DNA evidence and CCTV footage from the area on May 6, prosecutors say.

They were described as aged 24 and 31, originally being from the Comoros islands, and having a string of criminal convictions.

Video from railway stations and elsewhere showed that the two men had taken a train from Marseille to Nice on the afternoon of the shooting, gone to a hotel, and then made their way to the scene of the shooting, prosecutors say.

French media had earlier reported they had spent 500 euros ($680) on a taxi back to Marseille afterwards.

Sylvia Pastor, the dead woman’s eldest daughter, was released on Wednesday night.

Reports say Sylvia Pastor and Wojciech Janowski have been together for 28 years and have a teenage daughter.

[youtube 0_AZrsE7tGo 650]