TULSA, Oklahoma - Investigators released new information Monday in last week's train derailment in Tulsa. Burlington Northern Santa Fe Railway police believe vandals "tampered with a parked train's air brake system" which caused the crash.

Tulsa Police released several pictures that show at least two people walking along the tracks just before the collision.

The train cars that ran off the tracks are still there, waiting to be cleaned up. Meanwhile, investigators are waiting on leads. The most recent, four pictures, that could help close their case.

Some may say a picture is worth a thousand words. But in this case a few grainy snap shots may be worth a $100,000 reward.

"This is a significant dollar amount, as you indicated, and hopefully someone or that it will encourage someone to just think about what they saw," said Joe Faust, BNSF Railway. "If they have information that will help us, we would appreciate it."

Tulsa police believe the people shown in the grainy photos may have played a role in, or know something about, Friday's dangerous train derailment.

Railway spokesman Joe Faust says the train parked in North Tulsa to swap crews around midnight.

"The train was being staged at Trenton Street, it was mechanically sound and the train was never alone," he said.

Faust says it was while the crew exchange took place that someone tampered with a lever that keeps all the train cars together. That, Faust says, caused several cars to come loose, derail and hit another locomotive.

Osage SkyNews 6 was over the scene, and three days after the derailment, clean up crews still have a big job ahead of them.

It was a significant amount of damage done to the cargo, to the BNSF Railway, to the equipment and to the local real estate.

Tulsa police say railway workers took the pictures with a cell phone. The resolution isn't great, but you can see at least two people walking along Burlington Northern Santa Fe railroad tracks.

Police say the photos were taken just before the locomotive crashed near Dawson and Yale early Friday morning.

There are several businesses along the tracks - some of which may have security cameras. Railway police say they will be reviewing any and all surveillance video.

Police say anyone with information can call the BNSF tip line at 800-832-5452 or Crime Stoppers at 918-596-COPS.