A Philadelphia man was arrested Tuesday night in the death of a 2-year-old girl who was fatally shot in Kensington on Sunday afternoon, officials said.

Police identified him Wednesday morning as Freddie Perez, 30, the 100 block of East Westmoreland Street, in Kensington. Acting Police Commissioner Christine Coulter said tips from the public helped lead investigators to him.

“We’ve had people giving stuff early on, giving nicknames, giving information, and it restores my faith in saying everyone is outraged when a child is murdered,” Coulter told reporters at Police Headquarters.

She said a second suspect is being sought and appealed for more tips to find him.

Perez, who taken into custody in Chester, Delaware County, is expected to be charged with murder, nine counts of attempted murder, and conspiracy in the death of toddler Nikolette Rivera, as well as a related nearby shooting that occurred just minutes before she was shot, said Anthony Voci, chief of the Philadelphia District Attorney’s homicide unit.

Both men were believed to have been involved in two shootings that occurred within eight minutes and just a few blocks of each other in Kensington. Law enforcement sources said they believe the shootings were drug-related.

In the second of the two shootings, which occurred around 3:30 p.m. Sunday, 2-year-old Nikolette was killed when a gunman fired a round of bullets into her family’s home on the 3300 block of North Water Street. She was shot once in the back of the head while in her mother’s arms and was pronounced dead at the scene.

Coulter said Nikolette’s father, who was not in the house at the time, was believed to be the target of that shooting.

Two others who were inside the home were wounded in the shooting, including Nikolette’s 24-year-old mother, who was shot in the arm and grazed in the head by a bullet. A 33-year-old man who was cleaning the carpets inside was shot in the abdomen, police said.

Investigators do not believe that the man who was arrested Tuesday night fired any of the shots that killed Nikolette or injured others in her home.

Eight minutes earlier on the 400 block of East Clearfield Street in Kensington, law enforcement officials said, Perez and a second person — one carrying a rifle, the other a handgun — fired at a passing SUV. No one was wounded or killed in that shooting.

Locator map of Sunday's fatal shooting of Nikolette Rivera in Kensington, and an earlier shooting in the same area

In an interview Tuesday, Coulter said investigators have not been able to determine whether anyone who was shot in that incident was connected to the home where Nikolette was later killed.

Police have said the same rifle was used in both shootings, and Coulter said the second incident on Water Street could have been retaliation for the first shooting.

“We know [the incidents] are connected by ballistics,” Coulter said.

She added that although the shooter “clearly targeted" the Water Street house where Nikolette was with her family, investigators do not believe the shots were intended for anyone who was inside at the time. In addition to Nikolette, three other children were there, as well as Nikolette’s mother and grandmother and the man who was cleaning the carpets.

The gunfire left six bullet holes in the front of the house, and detectives recovered six fired rifle casings in the street.

The shooting of Nikolette was the second time in less than 24 hours that a child was shot in Philadelphia over the weekend. In Hunting Park on Saturday night, an 11-month-old boy was shot four times when someone fired at the car he was in, driven by his stepmother.

The incidents left Philadelphia officials and residents stunned this week and served as the latest example of gun violence in Philadelphia. Earlier this year, former Police Commissioner Richard Ross said the number of gun slayings in the city was “alarming.” As of Monday, 280 people have been killed in the city this year.

At a news conference Monday, a visibly upset Mayor Jim Kenney teared up at times, calling the weekend’s violence “horrible.” City officials asked the public to help bring the offenders to justice. A $30,000 reward was offered for information leading to the arrest and conviction in the shooting of Nikolette and in the case of the 11-month-old.

At a makeshift memorial Monday on the porch of Nikolette’s family, more than 40 candles burned next to a table of some of her favorite things. She loved makeup, her uncle said, and often asked if she could leave her lipstick on when she showered.

Anytime a candle was lit, she started singing “Happy Birthday.” She was supposed to be a baby shark for Halloween.