The older brother of the French Islamist who shot dead seven people was presented Sunday to a Paris judge to face charges of complicity in murder and of planning terror attacks, prosecutors said.
The judge must now decide whether to formally charge Abdelkader Merah, who denies helping Mohamed Merah kill three paratroopers, three Jewish schoolchildren and a trainee rabbi in a series of gun attacks.
"An inquiry into complicity in murder and criminal conspiracy with a view to preparing terrorist acts was opened Sunday" into Abdelkader Merah, the prosecutor's office said in a statement.
"Police inquiries have produced serious and matching evidence that suggest his participation as an accomplice in crimes relating to a terrorist enterprise is plausible," it said.
The suspect also faces the possible charge of gang robbery of a scooter, prosecutors added.
Merah, 29, denies helping Mohamed, 23, kill his victims but has said he was "proud" of him and admitted he was present when he stole the powerful scooter on which he fled after carrying out the murders, police said.
Abdelkader Merah and his girlfriend were taken in for questioning on Wednesday, a day before Mohamed was killed by police as he tried to shoot his way out of a 32-hour siege on his apartment in Toulouse in southwestern France.
The girlfriend was released without charge from custody earlier Sunday.
Police and prosecutors have described Abdelkader as a more radical Islamist than his brother.
Mohamed Merah, labelled a "monster" by President Nicolas Sarkozy, claimed to be an Al-Qaeda member killing to avenge Palestinian children and punish France for sending troops to Afghanistan.