LONDON — A Scottish house had been used as a makeshift bomb factory to carry out the terror attacks in London and Scotland, British media reported today.

Britain's terrorism threat level has been lowered following the capture of eight people connected with the three failed car bombings but authorities were still investigating the possibility of a sleeper cell operating in the country.

At least two of the suspects — mostly doctors — allegedly rented a house just a few miles from the Glasgow airport where two men crashed a gas-laden Jeep Cherokee into the barriers outside the main terminal. The two men slept upstairs and used the downstairs as a makeshift bomb factory, several British news outlets reported citing unidentified sources.

Brian Harvey, a 60-year-old construction worker who lives on the street where the house is located, said he had seen a green sport utility vehicle outside the property being searched. He said the car was nicer than most found in the neighborhood.

Police were still outside of the house this morning.

Two other suspects allegedly stayed at medical staff accommodation at the Royal Alexandra Hospital in Paisley, British newspapers reported. Scotland Yard refused to confirm any of the reports.

A British investigator, meanwhile, was questioning an Indian doctor arrested in Australia.

Australian police acting on information forwarded from British counterparts arrested Muhammad Haneef, 27, on Monday in the eastern city of Brisbane as he tried to board a flight with a one-way ticket, believed to be to India via Malaysia.

Haneef worked in 2005 at a hospital in northern England where another suspect arrested in connection to the failed attacks also worked. He moved to Australia last year and is one of suspects detained over the plot in which two car bombs failed to explode in London on Friday, and two men rammed the Jeep with gas cylinders into the entrance of Glasgow International Airport Saturday.

There have been 38 racist incidents in the Glasgow area since the attack, and tensions have been running high, police said.