For the second time in three months, police have raided Mitsubishi Motors' Tokyo headquarters while investigating charges of negligence similar to the one four years ago, when the company admitted to hiding vehicle defects for more than 20 years.

For the second time in three months, police raided Mitsubishi Motors' Tokyo headquarters while investigating charges of negligence similar to the one four years ago, when the company admitted to hiding vehicle defects for more than 20 years.

Following reported incidences of wheels coming off trucks and fatally injuring pedestrians, police have investigated the company on suspicions of professional negligence and this week expanded the search to include more offices and a manufacturing plant.

After a woman and her two sons were injured after being struck by a wheel that had come loose from a Mitsubishi trailer, investigators found that the hub linking the axle to the wheel was broken. Associated Press reported that Mitsubishi Motors denied any error in the production and design of its vehicles but admitted that inadequate checks led to the accident, which could have been avoided had the bolts been tightened properly.

One Mitsubishi spokesperson told the news agency that about 50 cases of loosening wheels were reported, though there were no further reports of injuries or great damage. Police believed that as many as 30 cases were reported before Mitsubishi decided to implement extra safety measures.

Four years ago, Mitsubishi Motors came under heavy scrutiny after it admitted to systematically hiding vehicle defects for more than two decades to avoid recalls, prompting an eventual recall of more than one million vehicles.