Oswald was to be transported in an armored truck as part of a long procession of police cars traveling from the Commerce Street ramp to the entrance to the county jail.
The armored truck was sitting atop the Commerce Street ramp. This was to be the vehicle that Oswald would be placed in to be taken to the county jail. The driver of the truck had concerns about backing the truck down the ramp, fearing that the truck would stall on it's way up the ramp after picking up it's very infamous passenger. The driver was also concerned with the overhead air conditioning ducts.
Fritz didn't learn of the plan to transfer Oswald in the armored truck until Sunday mid-morning. He objected heavily. Fritz went to Curry with the idea that the alleged assassin should secretly be transferred in one of the police cars in the procession and that the armored truck would be a decoy. Curry agreed and they set the plan into action.
Fritz ordered Lt. Rio Pierce to take one of the police cars from the basement, take it up the Main Street ramp and go around the block to the Commerce Street side to take the lead position in the procession to the county jail.
Jack Ruby wired the money to his dancer at 11:17 a.m. and headed to the top of the Main Street ramp as he walked out the door of the Western Union office, which was only a half block away from the top of the ramp. The money wire receipt was time stamped at 11:17.
As the car driven by Lt. Pierce made it's way up the Main Street ramp to begin it's trek around the block to the Commerce Street side, officer Roy Vaughn, who's sole job was to guard the top of the Main Street ramp, stepped out into the street to halt traffic so that Pierce's car could turn onto Main and head around the block. With Vaughn no longer guarding his post, Ruby entered the ramp and made his way down.
James Turner, an employee of WBAP-TV Fort Worth, was standing at the bottom of the ramp on the east side, near the railing.
He testified that shortly before the shooting of Oswald, he observed a man making his way down the ramp who he (Turner) was confident was Jack Ruby.
Det. Jim Leavelle spoke with Ruby while Ruby was in custody at City Hall. Leavelle asked Ruby how he got into the basement. Ruby stated that when the car driven by Rio Pierce came up the ramp and the guard went out into the street, he walked down the ramp.
Leavelle wanted to see if Ruby was being truthful so he asked his men if any of them knew who drove the car up the ramp just before the shooting. None of them knew who the driver was. Leavelle then went to Capt. Fritz and asked him who was driving the car. Fritz told Leavelle that he ordered Lt. Pierce to take one of the police cars in the basement and take it up the ramp to go around the block to Commerce Street.
None of Leavelle's men knew who drove the car up the ramp but Jack Ruby was perfectly aware of who was driving that car because he saw Pierce driving it with his own eyes.
Ruby gained entrance into the basement via the Main Street ramp.
Oswald was shot at 11:21 a.m., just four minutes after Ruby wired the money to his dancer. Ruby was in the basement no more than forty-five seconds before he shot the wretched waif Oswald. If Ruby had arrived in the basement much earlier, he would surely had been noticed and made to leave.