LONDON — Pavlo Lapshyn, a gifted 25-year-old engineering student from Ukraine, had come to Britain after winning a prestigious placement at a software company. A special awards ceremony had been held at the British ambassador’s residence in Kiev, and in April Mr. Lapshyn arrived in Birmingham.

Five days later, he took a knife, roamed the streets of a multiethnic Birmingham neighborhood and stabbed a bearded man three times in the back, killing him. He did not know the man, Mohammed Saleem, an 82-year-old grandfather of 22 who was walking home from evening prayers at a local mosque.

Mr. Lapshyn, who pleaded guilty to murder and other charges in the case this week and is expected to be sentenced on Friday, has shown no remorse.

“I have a racial hatred, so I have a motivation,” he told police officers who interviewed him before trial. “I would like to increase racial conflict, because they are not white and I am white.”