AUSTIN, Texas >> It was past midnight when the call finally came crackling over the radios of agents pursuing the man who had been terrorizing Austin with his homemade bombs. An officer had sighted an aging red Nissan Pathfinder in the parking lot of a Courtyard by Marriott hotel in suburban Round Rock.

The radios went silent for a moment as officers in a fugitive task force organized by the U.S. Marshals Service pondered whether they had found their suspect, Mark Conditt, 23, who had been identified by surveillance footage. Within minutes, Austin’s police department mobilized a SWAT team to proceed to the site.

Stay away from the red SUV, warned the marshals, veterans of outlaw hunts across the Texas badlands who have seen how such things can go.

“We were trying to plan a safe approach, a Murphy’s Law plan for everything that could go wrong,” said Brandon Filla, a deputy marshal from the service’s office in Austin. “He could have been doing surveillance on his vehicle from a window in the hotel, ready to blow up anyone who went near it.”

The team had been tracking the suspect for hours, clued to his location by his cellphone, scouring every hotel and restaurant in the area. They knew the explosive packages he had planted, six in all, that had left two people dead and four others injured.

“We knew what the suspect was capable of,” Filla said.

The story of how law enforcement agents were finally able to stop the bomber’s deadly attacks emerged Friday, as the police continued to review evidence recovered at the suspect’s home in nearby Pflugerville and began to release details of an operation that ended in a fatal confrontation near the hotel in Round Rock. The work of the marshals was but one part of an extraordinary puzzle that made up the last 24 hours of the serial-bomber investigation.

In the predawn hours of Wednesday, emotions were on edge among the dozens of officers lying in wait. Some had hardly slept in days. Like other residents of this fast-growing city, they had grown apprehensive about going near anything resembling a package. Pressure to catch Conditt was growing intense.

Was he inside the hotel? Filla wondered.

Agents checked with the hotel management, who confirmed that Conditt was not checked in as a guest. They kept their eyes trained on the Nissan in the parking lot. Then an officer peering through binoculars glimpsed exhaust coming out of the tailpipe.

The headlights were off. But the vehicle started to move out of the lot.

A SLIP-UP ACCELERATES THE CASE

The authorities knew Conditt would send or place another homemade bomb — the question was when, not if. A series of leads had brought investigators to him, including surveillance footage inside and near a FedEx store where he had shipped two packages loaded with explosives. Starting with the license plate from a different truck he drove, agents were able to track his cellphone number and the construction gloves he had worn while shipping the bombs.

The clues all came together to where Conditt was Wednesday morning, in the darkened parking lot off Interstate 35.

The showdown started with an apparent mistake.

At one minute past 4 p.m. Tuesday, paramedics were notified about an “unknown medical alarm” at Conditt’s home in Pflugerville. Two paramedics from the Pflugerville Fire Department responded. A person inside the home — it was unclear whom — answered the door and told the medics no one there had called 911. The paramedics cleared out at 4:11 p.m.

From an incident report released Friday by the Pflugerville Fire Department, it now appears that a request by investigators for paramedics to remain near the house was relayed instead as a call for immediate medical aid to the residence. It is possible that Conditt himself had come to the door or was home at the time, and began to suspect that the authorities were closing in.

Finding paramedics at his door could have been the reason Conditt drove to Round Rock and appeared to be taking steps that signaled he knew the police were on his trail. At some point in the hours to come, he left a roughly 25-minute recording on his phone that officials described as a confession. Law enforcement officials said the miscommunication involving the paramedics was under review.

CLOSING IN

On Tuesday night, investigators were still sorting through a multitude of tips and blind alleys.

The local, state and federal agents hunting the bomber wondered if he had struck again. About an hour after the paramedics had left Conditt’s residence in Pflugerville, the team of investigators had converged on a Goodwill store in south Austin shortly after 5 p.m. in response to a report of an explosion. That incident ended up being unrelated: Military-style ordnance that someone had donated had ignited and injured a worker. It took attention away from Conditt.

But not for long. Later that evening, the police closed Main Street in Pflugerville.

It was not until later that they traced his vehicle to the Courtyard by Marriott in nearby Round Rock. When Conditt pulled his Pathfinder out of the parking lot, a stream of vehicles slowly followed. Filla, the deputy marshal, described it as the opposite of a high-speed chase. Agents, he said, were hoping to capture Conditt alive and avoid any harm to themselves.

Using what he described as a “tactical vehicle maneuver,” the SWAT team managed to cautiously push Conditt’s vehicle onto the edge of a service road just off Interstate 35. Officers approached the vehicle, but were stunned by an explosion triggered by Conditt as they moved in.

“Bomb, bomb, bomb!” some in the vicinity yelled. At one point, one of the officers fired his weapon; another was thrown back by the blast and injured.

Other officers quickly tried backing up their vehicles but found they couldn’t go very far since so many official cars — from the marshals to local police departments, the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, and the FBI — had arrived at the site.

“It resembled a law enforcement funeral procession,” Filla said. “That’s how many of us were there.”

Hours after it was all over on Wednesday, the Austin police chief, Brian Manley, told reporters assembled nearby that the bomber was dead, although he declined to identify Conditt at the time.

“Late last night and early this morning, we felt very confident that this was the suspect in the bombing incidents that took place in Austin,” Manley said.

“The suspect,” he said, “is deceased.

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