Federal investigators found three witnesses who said the commuter train involved in the worst train accident in California in the past 15 years had a green light as it headed toward the deadly impact, according to a report from the Los Angeles Times.

The three witnesses told investigators they saw the commuter train at the Chatsworth, Calif., Metrolink station before the crash and they saw the final signal it received before heading toward the collision with a Union Pacific freight train.

The statements given by the witnesses are in contradiction with the reports of the National Transportation Safety Board which found out that the final signal of the Metrolink commuter train was red.

The train engineer, Robert Martin Sanchez, was sending and receiving text messages moments before the fatal impact last month. Although the 46-year-old engineer had sent and received numerous text messages that day and in the period before the crash, investigators couldn’t establish if he was doing that when he missed the red trackside signal (if the signal was in fact red).

According to a record of the engineer’s cell phone, he received a text message at 4:22:01 p.m. and another one at 4:21:03 p.m. At 4:22:23 p.m. the fatal impact took place. These were the last messages he read, but Sanchez received 7 and sent 5 text messages between 3:00 p.m. and the time of the crash.

As a consequence, Californian authorities imposed a ban to use cell phones by railroad employees during their shifts. A commuter train engineer who used his mobile phone while on duty shortly after the deadly accident has been suspended.

The terrible train crash killed 25 people and injured more than 135.