British police arrested a suspect early Saturday over the brutal stabbing murders of two French students.

Officers detained a 21-year-old man on a street in southeast London at about 3:40 a.m. (0240 GMT), police said. He was being held at a London police station.

Police would not say whether the arrested man was the prime suspect in the case, and appealed for witnesses to come forward.

Laurent Bonomo and his friend Gabriel Ferez, both 23, were bound and stabbed to death at Bonomo’s rented apartment, near where the arrest was made, on Sunday night. Bonomo had been stabbed nearly 200 times while Ferez received nearly 50 stab wounds. Their bodies were then set ablaze to destroy evidence.

Both were promising bioengineering students taking part in a three-month DNA research project at Imperial College in London.

Police said Friday the murders may be linked to the theft of two PlayStation game consoles, which they believe were taken from the apartment the night of the killings. A laptop computer was also stolen from the apartment six days before the attack.

The brutal killings have shocked a country already worried by a spate of knife attacks involving young people. Eighteen teenagers have been stabbed to death in London this year, and police in the city say the fight against knife crime has overtaken terrorism as their top priority.