Police on Thursday found a suitcase thought to contain the remains of a little French girl allegedly murdered by her Israeli grandfather and dumped in a river in a grisly case that has shocked the country.

After five weeks of intensive and frustrating searches, divers pulled from the murky waters of a Tel Aviv river a red suitcase fitting a description given by the grandfather of four-year-old Rose during interrogation.

"This was a very long and complex investigation with very problematic parents that required a lot of creativity. The result was that we found the body of a five-year-old girl today," police commissioner Dudi Cohen told reporters on the banks of the Yarkon river.

Ronny Ron, an Israeli taxi driver who in a bizarre love triangle was living with Rose's mother -- his former daughter-in-law -- had initially told police he had beaten the girl to death and put the body in a red suitcase which he hurled into the Yarkon river. He later retracted his confession.

Search teams and dozens of volunteers had combed the river and surrounding areas for weeks before Thursday's breakthrough.

Ron, 45, lived near Tel Aviv with Marie-Charlotte Renaud, 23, a Frenchwoman previously married to his son Benjamin, who is Rose's father.

A Tel Aviv court on Tuesday remanded Ron and his former daughter-in-law, who is also suspected of involvement in the gruesome murder, in custody for 10 days.

Benjamin divorced Renaud about three years ago after he found out she was having an affair with his father. Ron and Renaud now have two children of their own.

Rose's maternal grandmother, Betty Sghaier, on Thursday called for the little girl's remains to be flown to France.

"I want Ronny and Marie-Charlotte to be punished. They should languish in prison... they have no heart," she said, charging that the couple were "monsters, murderers."

Described by police as "one of the most shocking in the country's history," the case has dominated headlines in Israel for weeks.