PARIS: French police arrested former Liverpool striker Djibril Cisse and three other people on Tuesday over a suspected attempt to blackmail France soccer international Mathieu Valbuena using sex video footage, officials said. All four were taken into custody west of Paris and in Marseille as part of an investigation into alleged extortion and offences punishable by at least five years in jail, the public prosecutor's office said. Cisse, a former teammate of Valbuena's at Marseille, was apprehended because he knew the others involved, but is not suspected of being an instigator, a police official said. The attempted extortion involved video footage of sex recorded on a mobile phone, said the official, who declined to be identified, a common practice in France for official police spokespeople. Cisse, 34, who retired earlier this year, was taken into custody at 6 a.m. (0500 BST), the prosecutor's office added. Valbuena, 31, plays for Ligue 1 club Olympique Lyonnais and the French national team.