For the Twitter feed of London’s Metropolitan Police, Friday seemed like an ordinary day.

It announced some arrests. (Teenagers obstructing a road at a protest.) A man was jailed in a murder case (life, for killing a “friendly pensioner”).

Then things started to go sideways.

For about 40 minutes, the account spewed messages, some irreverent, others incomprehensible, that suggested perhaps the police were no longer in charge.

“XEON IS THE BEST FIGHTER IN SCOTLND,” one message read, without elaborating.

Soon the account started hurling expletive-laden messages denigrating police officers, making it clear that the account had been compromised. The posts would appear, then a few minutes later would be deleted, suggesting that some sort of cyber tug-of-war was underway.

Another message read, “no comment get my lawyer.”

“FREE DA GANG!! #CHUCKLINGHELLA,” one post read, including an obscenity directed at police officers.