A school bus, which was involved in a fatal accident in Offaly in 2006, was "clocked" five years earlier, a court has heard.
Schoolboy Michael White, 15, died on 4 April, 2006 when the bus went out of control and flipped over on a bog road just outside Clara.
The back axle had come off the bus.
David O'Reilly, acting on behalf of O'Reilly Commercials Ltd of Ballinalack, Mullingar, Co Westmeath has pleaded not guilty to four charges relating to failing to note or verify defects when they tested the bus between 5 and 6 August, 2005.
The defects include a missing bolt in the right rear suspension spring of the bus, and a fracture in the chassis.
Garda Adrian Tucker told Caroline Biggs SC, prosecuting, that he believed the mileage on the bus tachograph was altered.
He said his examination of the tachograph chart showed that the mileage of the 1989 Mercedes bus in September 2001 was 96,619 km.
He said that at the time of the crash the mileage was 48,251km.
John Sheehan, an inspector with the Health and Safety Authority, told Ms Biggs that he believed the clock was "reconditioned" in and around 2002.
He said: "It was clocked".
Inspector Sheehan told Diarmaid McGuinness SC, defending, that he wrote to the Department of Transport in 2008 seeking all records for the bus.
He said the department was unable to provide any test results but provided a table of test dates.
Counsel put it to him that this stated that the vehicle was tested on 1 September, 2005.
The prosecution alleges that Mr O'Reilly tested the bus first on 6 August and re-tested it on 1 September.
Mr McGuinness has said that his client contends he provided the then owner with a snag list of necessary repairs in August and only carried out the roadworthiness test on 1 September.
The bus was examined by a mechanic between those dates and was later sold on to a Clara bus hire firm.
The trial, which is in its ninth day, will continue on Wednesday as the jury are unable to sit tomorrow.