Police on Monday said the explosive devices used in Friday's attacks in Malegaon contained RDX, and released the sketch of a man seen near a mosque where one of the blasts occurred.

A report from one of the three laboratories that tested samples from the blast sites stated that the bombs contained a mixture of RDX, ammonium nitrate and fuel oil, Nashik's Superintendent of Police Rajvardhan told reporters in Malegaon.

Rajvardhan also released a sketch prepared on the basis of descriptions provided by eyewitnesses of a man who was seen outside the Hamidia mosque around the time of the explosions.

This was the third sketch issued so far by police.

On Sunday, they had released sketches of two men who bought bicycles believed to have been used to plant the bombs.

"Nobody has been arrested, nobody has been detained so far," Rajvardhan said. Police were still questioning "some people" and some witnesses, he said.

Investigators had gone to some places to follow up leads, he said, but did not give details.

When it was pointed out that the contents of the bombs used in Malegaon were similar to those used in the July 11 train bombings in Mumbai, Rajvardhan said, "We can't say anything till we get reports from all the agencies (that are testing the samples)."

Thirty-one people were killed and nearly 300 injured in four blasts in Malegaon on Friday.