Army bomb disposal experts were testing a suspect substance last night after dozens of households were evacuated during a bomb scare in a Birmingham suburb.
West Midlands Police officers found the substance at an address in Long Nuke Road, Bartley Green, after a raid on the house at 8am.
Two hours later, the army's Explosive Ordnance Disposal unit was called and the material was taken to a laboratory for testing.
A 100-metre cordon and evacuation zone was made as a precaution and traffic diversions put in place. The cordon was later lifted by 1.30pm after the removal of the substance. A West Midlands Police spokeswoman declined to confirm why the premises was searched but said no arrests were made during the raid.
She said the property was empty at the time of the police search and the raid was not linked to terrorism.
"We can confirm this is not related to terrorism. The warrant was executed under the Theft Act," she said.
Police last night were still unable to confirm what the substance was.
A spokeswoman said: "At this stage and until the tests are carried out, we do not know what the substance is. If we find a substance that cannot be identified but could contain an explosive substance, then we automatically implement our Emergency Planning Procedures in conjunction with our partner agencies in the interests of public safety. Public safety is paramount in such circumstances."
Families living within 100 metres and evacuated from their homes were given shelter in nearby Shenley Court Senior School, where council officers provided refreshments.
One resident, Kathleen Wright, who lives just two doors from the terraced house, described how police banged on her door shortly after 9am and told her to evacuate her home.
Mrs Wright, aged 49, said: "I saw the police pull up at about 7.30 and they went inside for a couple of hours.
"Some others came and some went and it was a few hours later when I had a knock on the door and the policeman said: 'You've got two minutes to get out because there's some stuff in there and we're afraid it could go up at any minute'.
"I just had enough time to grab my coat and pick up my dog - I didn't even have enough time just to grab my husband's heart tablets."