PHILADELPHIA (CBS) - The memorial at the corner of Friday night’s crash is growing. Friends and family have set up candles and written messages to Danny Roman, 36, who died in the crash. His wife, Jenny Santiago, 26, and their son Jaeden, 4, were rushed to the hospital in critical condition.

The crash happened after a police pursuit through North Philadelphia. Officers stopped Gregory Alston,39, for traffic violations. But when they asked for his license, they say he flashed a gun and sped off.

“Pursuits are very dangerous, so we’re always looking for ways to minimize the dangers to the police and the public,” says Deputy Commissioner Richard Ross.

Ross says the police department has a very restrictive policy for starting police chases. It has to be for a forcible felony or a suspect with a deadly weapon.

In this case, police say Alston threatened police before driving away. They pursued with the police helicopter following from above. They did not box the car in or try to burst his tires because by department policy that is forbidden. Police say they automatically initiate an internal affairs investigation after any police pursuit.

“We don’t use spike strips. We don’t ram vehicles. We don’t box vehicles in,” says Ross.

After the crash, police arrested Alston in a nearby lot. Ross says it is important to remember here who caused the crash that took a life.

“There was an individual who caused all this and it wasn’t the police. There was a tragedy that resulted and our prayers go to the Roman family.”

As of Monday night, 4-year-old Jaeden has been released from the St. Cristopher’s Hospital for Children.

There is no timetable for the completion of the investigation. Police say they will interview everyone involved and listen to police radio.