Two people were killed and two others were injured in this pre-dawn crash in Chevy Chase. (Courtesy of NBC News Channel 4)

The last time Nikita Nelson saw her son and nephew alive was 10:30 Thursday night. It was late, but there was no school the next day. The boys sat on a sofa, eating chips and joking inside their home in Northwest Washington. She went to sleep.

Within three hours, the two boys — 14 and 16 — were in the back seat of a stolen Toyota Echo that had made its way into Montgomery County, according to authorities. Behind the wheel was a 16-year-old; in the front passenger seat was an 18-year-old.

Someone in the car noticed that police were following them, officials said, and the small sedan sped south down Connecticut Avenue, heading for the District. Officers flipped on their lights and sirens and pursued the vehicle.

At Chevy Chase Circle, the Toyota spun out of control, smacked into a tree and caught fire, police said. Officers pulled the driver and front-seat passenger out. One of the officers used his tactical baton to smash out a back window. Others sprayed the roaring flames with small fire extinguishers. But it was too late for the two in the back.

Emanuel Nelson, 16, and Kyree Nelson, 14, died in their seats, according to police accounts and Nikita Nelson.

Hours later, at 6 a.m. Friday, officers knocked on Nikita Nelson’s front door and asked if the cousins lived there. Assuming that they were in trouble, she recalled, she went to get them. But their beds were empty.

“I still don’t believe it,” she said from her home Friday. “I really don’t believe it.”

The car was stolen in Montgomery a week ago, and police officials would not say if they know who took it or whether all the teenagers inside knew it was stolen.

Authorities did not say how fast the car was traveling when it crashed, only that it was above the 30 mph speed limit.

Police officials said the officers involved appear to have followed proper procedures during the pursuit, despite its tragic end. They said a standard review will be conducted.

Police identified the driver as Reynard Osman, 16, who lives in the District. He was being treated at a hospital for injuries that were life-threatening, and no charges had been filed in the case as of Friday evening. The front-seat passenger, Reeco Richardson, 18, also of the District, suffered less-serious injuries. Family members of the two could not be reached to comment.

As word about the crash spread Friday, friends and relatives gathered at Nelson’s home, flipping through family photos, crying and remembering the cousins.

Emanuel, a 10th-grader at Coolidge High School, went by the nickname ManMan. He played junior varsity football and was slated to start on the varsity squad next year. He dreamed of playing football at Penn State University and becoming a veterinarian.

His mother, Nikita, said she also cared for his cousin Kyree, who lived in the home and was enrolled at E.L. Haynes Public Charter School. Kyree played soccer and was known to pull pranks on family members. His nickname was Thumb because he had sucked his thumb for so long.

“We tried everything to get him to stop. Hot sauce, putting something on his gums,” said his mother, Latrice Nelson.

Close friends since they were young, the cousins had just learned that they’d been accepted into the District’s Summer Youth Employment Program. “They loved to look nice,” Nikita Nelson said, “and loved the young ladies.”

It wasn’t clear how all the teenagers came to be riding inside the Toyota Echo. It was reported stolen six days ago, late Sunday morning, from the Forest Glen area in Montgomery, said Officer Rebecca Innocenti, a Montgomery police spokeswoman. Two other cars were reported stolen around that time in that area – a Mitsubishi Eclipse and a Honda Odyssey minivan. Police do not know if the thefts were related.

Shortly after 1 a.m. Friday, a patrol officer in the East-West Highway area west of downtown Silver Spring headed toward Bethesda as the bars were closing.

He spotted the Echo, saw something suspicious and typed the license plate number into his in-car laptop, according to police. Officials declined to say what made the officer suspicious. But it’s not uncommon for late-shift officers to frequently check license plates during their shifts.

The officer, a seven-year veteran of the force, learned that the Echo had been stolen. He called for backup, not wanting to make a felony stop by himself, police said. Several other officers quickly converged on the area, said Capt. Paul Starks, a police spokesman.

The Echo went west to Connecticut Avenue, a main north-south road, and turned left, heading south, Starks said.

Officers made a plan to stop the car near the National 4-H Youth Conference Center. But they never got a chance to do so, Starks said.

The Toyota sped south. Officers turned on their lights and sirens and followed.

Montgomery Police Chief J. Thomas Manger said Friday that based on his initial review, the chase was proper. Montgomery police procedures allow officers to pursue stolen cars under certain conditions — principally regarding safety and traffic concerns. At the time, officials said, Connecticut Avenue was dry and traffic was light to nonexistent.

“All the information I have so far indicates the officers were within our policy guidelines,” Manger said.

At Chevy Chase Circle, the Toyota driver veered to the right, and the car began skidding left and rotating clockwise, said Capt. Tom Didone, commander of the police department’s traffic division.

Now headed toward the middle part of the circle, the car jumped a curb, skidded through grass and slammed into a tree, Didone said.

Three, possibly four, cruisers quickly pulled up. They saw smoke quickly turn to flames, officials said.

Officers pulled the front-seat passenger — Richardson — from the car. His clothes were on fire, police said, and officers rolled him on the ground to extinguish the flames. Officers pulled the driver, Osman, through the passenger door.

“If the officers had not rescued the front-seat passengers, they likely would have perished in the fire as well,” Manger said.

Officers tried to get to the two back-seat passengers, but “the flames became too great,” Starks said.

At Coolidge High School, football coach Natalie Randolph said she had Emanuel Nelson in her environmental science class last semester.

“He was an awesome kid, gregarious and happy,” she said. “He worked hard when he was here. He had to deal with a lot about who to hang out with and stuff. But when he made the decision to do what he wanted to do, he did it.”

Emanuel was a 5-foot-10, 180-pound starting linebacker on the junior varsity football team who was slated as a starter on the varsity team next season, Randolph said. She described him as a “hard hitter” and “smart football player.”

“Like any teenager, he was straightening things up,” Randolph said. “All his teachers pretty much loved him. He struggled at first, but he was getting better.”

Keino Wilson, the school’s athletic director, said football meant so much to Emanuel that he cried on Wilson’s shoulder when he didn’t have his physical paperwork completed in time for the first football game this fall.

And just this week, Emanuel saw Wilson at the school. “He just saw me and gave me a hug and told me he loved me,” Wilson said. “I keep replaying that in the back of my head.”

Staff writers James Wagner and Mary Pat Flaherty, social media producer T.J. Ortenzi and staff researcher Magda Jean-Louis contributed to this report.