Police found no evidence of terrorism or radicalization by a teenager who fatally stabbed a Florida woman and wounded five others in London’s Russell Square, police said Thursday.

Zakaria Bulhan, a 19-year-old Norwegian-Somali, went on a knife rampage Wednesday night through the tourist hub, sparking fears of another ISIS-related attack in Europe, officials said.

Darlene Horton, 64, of Tallahassee was killed a day before she and her husband, Richard Wagner, a psychology professor at Florida State University, were expected to return to the US, the Tallahassee Democrat reported.

He taught in the summer session at FSU’s London Study Program, the school said in a statement.

“There are no words to express our heartache over this terrible tragedy,” FSU President John Thrasher said.

Assistant Commissioner Mark Rowley, the top counterterrorism official at the Metropolitan Police, said “all of the work that we have done so far increasingly points to this tragic incident as having been triggered by mental health issues.

“At this time we believe this was a spontaneous attack and the victims were selected at random.”

Cops used a stun gun to subdue Bulhan, who emigrated to Britain from Norway in 2002. He was charged with attempted murder.

London Mayor Sadiq Khan said “there is no evidence at all that this man was motivated by Daesh” — another name for ISIS — or similar groups.

The wounded victims were an American, two Australians, an Israeli teen and a British man. Only the British victim remained hospitalized Thursday.

Horton was repeatedly stabbed in the back before she was helped by a family of Spanish tourists, the Telegraph of the UK reported.

A witness said he tried to console her before she died at the scene.

“The victim said something about: ‘He’s still here! He’s still here!’ After that she was not lucid. That’s when I saw someone. He was meandering about. He was very disturbed,” the witness told The Daily Mail.

A bicyclist on his way home from work was flagged down by the Spanish family.

The 40-year-old Brazilian said he was told the attacker had been making “sweeping, stabbing motions” but “didn’t say anything.”

“I saw a white woman slumped against the railings with injuries and she was being helped by a young Spanish girl who looked around 16 years old,” he said.

“She had been stabbed in the back several times, and I called 999. An Englishman, in his mid-40s, had been stabbed in the ribs under his left armpit,” he added. “He said, ‘I’m OK, I’m OK, please help the woman!’”

The wounded Israeli citizen was identified as Yuval Levkovsky, 18, who was visiting London before enlisting in the Israeli army.

She said she was walking with her grandfather back to their hotel after dinner when she heard screams.

“I heard it and my Israeli instincts started to kick in,” she told Israeli Army Radio, recalling she suddenly saw two men running toward them. “I suspected it was a terror attack and that the two were trying to escape. I went up to one of them to help and felt a pain in my arm.”

Levkovsky said the second man chased and caught the attacker,.

“I’m not afraid in Israel, so I have no reason to start being afraid in London,” she told Israeli Ynet news.

The incident took place near the scene of one of four suicide attacks that killed 52 people in London on July 7, 2005. One of the bombs exploded on a double-decker bus in nearby Tavistock Square.