Three teenagers arrested following an arson attempt in which a gas pipe was fed through a mosque window have been released on bail.
The incident in Stoke-on-Trent is being treated by police as a deliberate racist attack.
Officers were called to Regent Road at 0630 GMT on Friday after CCTV footage showed smoke emerging from inside the building.
A fourth teenager who was arrested faces no further action.
Police said inquiries were continuing although a forensic investigation had now ended.
"A number of items have been secured by police scenes of crimes officers which will now undergo a series of forensic tests to recover any further evidence which could help identify the persons responsible," a spokesman said.
BBC News
