Following Friday's mass shooting at a Colorado movie theater, police are slowly making progress getting into the suspect's apartment, booby-trapped with several layers of deadly explosives. Locally, the commander of Allentown's bomb squad called the situation a "worst-case scenario" for explosives crews.

With a bang, Colorado authorities detonated the first of many explosives Saturday morning that were left in the apartment of mass shooting suspect James Holmes.

"This trip wire was set up to clearly detonate when somebody entered that apartment and it was set up to kill that person," said Sgt. Cassidee Carlson with the Aurora (Co.) Police.

For Allentown's bomb squad commander, Lt. Charles Haydt, a small apartment booby-trapped with homemade explosives is his worst nightmare.

"We don't know what they have, what they've made, what they have to stop us from entering," he said.

Authorities have said Holmes' apartment is a minefield. Saturday morning, they used what's called a "bottle shot" to detonate an explosive by the front door.

"A bottle disrupter is a bottle of drinking water with explosives in the center of it," said Haydt. "So when the explosives detonate, you're actually using the water to disrupt the device."

Next, crews face about 30 so-called "improvised grenades," described as similar to fireworks but more concentrated. Finally, there are several containers filled with a mix of liquid accelerant, powder, and bullets. Crews hope to remove the bombs and transport them someplace safer for detonation. It's a move Haydt called extremely risky.

"Any time you try to move it, you're more or less aggravating something that is designed not to be aggravated," he said.

According to Haydt, one thing is certain: this will not be a quick operation.

"In our field, slow is better," he said. "Rushing is just going to get you hurt."

Local bomb squads have to get re-certified every three years, where they train for all kinds of scenarios. According to Haydt though, something this massive is very unusual.