HOUSTON — The police officer in McKinney, Texas, who resigned after a cellphone video was circulated showing him shoving a black teenager in a bikini to the ground outside a pool party offered an apology Wednesday through his attorney, who tried to explain the officer's actions by saying that he was under stress after responding to two earlier calls involving a suicide and a suicide attempt.

Before arriving at the pool party on Friday, the officer, Cpl. David Eric Casebolt, had helped console the grieving widow of a man who had shot himself in the head in front of his children, and had assisted in photographing the body, and then in a separate case calmed a teenage girl who was threatening to commit suicide by jumping off her parents' roof, said his attorney, Jane E. Bishkin.

"The nature of these two suicide calls took an emotional toll on Eric Casebolt," Bishkin told reporters in Dallas, adding, "With all that had happened that day, he allowed his emotions to get the better of him."

"He never intended to mistreat anyone, but was only reacting to a situation and the challenges that it presented," Bishkin said. "He apologizes to all who were offended."

The cellphone video, posted to YouTube, captured the latest police encounter to touch off a nationwide debate over how white officers respond to situations involving African-Americans. Casebolt, who is white, was one of several officers who responded to a report of a fight and a disturbance early Friday night at a pool in Craig Ranch, a predominately white subdivision in McKinney, a fast-growing suburb about 30 miles north of Dallas. Police officials said several juveniles who did not live in the area had refused to leave and had begun fighting.

In the video, Casebolt can be seen chasing some teenagers and is then heard cursing and shouting at them to go home. The black girl wearing a bikini can be seen walking around the area, and at one point, Casebolt approaches her and a group of other teenagers and tells them to leave.

She appears to linger, and Casebolt then takes her down on the grass by the head, arms and neck, and yelling, "On your face!"

The girl does not appear to resist as she lies facedown on the grass. Casebolt places both his knees on her back, and later one knee. The girl is seen crying and asking for her mother.

Several people rush toward Casebolt as he grabs the girl, and he pulls out his handgun. Officers chased one man, who was arrested on charges of interfering with the duties of a police officer and evading arrest. The charges were later dismissed.

The girl - Dajerria Becton, 15 - was detained and later released to her parents, police officials said. A lawyer for Becton told reporters that Casebolt's stressful encounters earlier in the day were not a defense for his actions, which she described as "inappropriate, excessive and without cause."

"Stress comes into our lives as attorneys, as reporters," said the lawyer, Hannah Stroud. "So using that as an excuse, or what sounded like a defense, it didn't bother me, but I wasn't sure if it perhaps belittled the apology a little."

Stroud said she was exploring legal options, including filing a federal civil rights lawsuit alleging excessive force. She said that Becton was an invited guest at the pool party, and that after she was asked to leave, she complied. "But when she asked for her bag so that she could call for her aunt, who is her legal guardian, she was pushed to the ground, grabbed by her head, and her face was shoved into the ground," Stroud said.

Bishkin said the video depicted "a small part of Eric's actions that day." When the report of a disturbance at the pool first came over the radio, Bishkin said he was reluctant to respond "to a simple trespassing call given what he had just been through." Once on the scene, she said, he did not target minorities, detaining a white female not shown in the video. But she added that his efforts to gather information were hampered by some teenagers who were instructing others to defy the police.

On Tuesday, the chief of the McKinney Police Department, Greg Conley, said that Casebolt would keep his pension and benefits after his resignation, but that he remained under investigation. The police department is investigating whether to bring criminal charges against him.

Casebolt, a 10-year veteran of the department who was once named its Officer of the Year, was not at the news conference. Bishkin and leaders of the McKinney chapter of the Fraternal Order of Police said that he had received numerous death threats and that those threats had forced him and his family from their home.

"He's worried for his family," Bishkin said. "He's worried he may be followed. Until that threat subsides, he's going to be in an undisclosed location."

Racial tensions preceded the officers' arrival at the party. A black teenager, Tatiana Rhodes, 19, said in a YouTube video interview that her family lived in Craig Ranch and had hosted the pool party and cookout for friends. A fight started after a white woman used racial slurs and told Rhodes to "go back to my Section 8 home," she said. She told the interviewer, E. Johnson IV, a photographer, that another white woman then hit her in the face.

Civil rights groups, including the National Bar Association, a predominantly African-American legal group, gathered in McKinney on Wednesday to call for reforms and for an independent investigator to look into the episode involving Casebolt.