LONDON - British serial killer Stephen Port was sentenced to life in prison without parole on Friday for the murders of four young gay men whom he met online.

The case has opened up questions about policing in Britain, as top security officials have admitted missing “potential opportunities” while investigating the deaths attributed to Port, possibly leading to him killing again, reports the BBC.

Judge Peter Openshaw said Port should die in prison for his “dreadful offenses.”

Get Breaking News Delivered to Your Inbox

Relatives of the victims cheered and clapped as the sentence was announced in the Old Bailey courthouse.

Port was convicted by a jury on Wednesday of plying his victims with drinks spiked with lethal doses of the drug GHB, raping them when they were unconscious and dumping their bodies in and around a nearby graveyard.

The 41-year-old chef was also convicted of 18 other offenses, including four rapes and four sex assaults, against several other men.

The U.K.’s independent police watchdog is investigating why detectives did not initially link the deaths of the four murder victims, all in their 20s, whose bodies were found near Port’s home in east London over a 15-month period.

Police began investigating the deaths as potential homicides only when the family of Port’s final victim, Jack Taylor, pressed for action.

“We finally have justice for Jack and the other boys,” Taylor’s sister Donna said outside court, according to the BBC. “A sick and twisted scumbag will never be able to hurt or destroy any other family’s life. Jack can finally rest in peace. We will always be completely heartbroken.”

The Guardian reports that the case, in which the killer said he was targeting so-called “twinks,” is drawing intense scrutiny and could lead to punishment for some police officers.

According to the Guardian: “Seventeen police officers are facing investigation for possible misconduct over the catalogue of failures in catching Port. The Met is now re-examining 58 unexplained deaths involving the drug GHB from a four-year period, across London, in case signs of suspicious death were missed.”