Merseyside Police have been granted more time to question a second man suspected of murdering an off-duty police constable.
Pc Neil Doyle, 36, was attacked in Liverpool city centre in the early hours of Friday during a Christmas night out with colleagues.
A 28-year-old man from Huyton was arrested on suspicion of murder later that day and will remain in custody for questioning until tonight.
Today, the force said they have also been granted an extension to continue to question a 30-year-old man from Huyton who was arrested on Saturday.
The Christmas and New Year holiday season will see drivers stopped by police and tested for drugs by the side of the road in a war on drug-driving.
The Telegraph has reported that the Home Office approved roadside testing kits that will analyse samples of saliva instantly to detect illegal substances as well as so-called "legal highs".
It said that police officers will also use the kits to catch drivers who have taken prescription medicines like strong painkillers, sleeping pills and drugs to treat anxiety, that can hinder concentration on the road.
It has been reported that ministers will order police to carry the "drugalyser" kits alongside conventional "breathalysers", which test motorists for alcohol consumption.
A second man has been arrested on suspicion of murdering off-duty police constable Neil Doyle in Liverpool city centre, Merseyside Police has said.
A 30-year-old man from Huyton has been arrested and taken to a police station to be interviewed by detectives.
A 28-year-old man, also from Huyton, who was arrested last night after handing himself into police is still being questioned.
The newlywed wife of a police officer who was killed in an assault in Liverpool city centre while off duty has issued a tribute to him.
Neil was very well loved by all of his family, friends and colleagues and it is a great loss to us all.
We are finding it extremely difficult to come to terms with what has happened and need time to be left to grieve.
The couple got married in July and were due to go on their honeymoon next month.
Police believe three men were involved in the attack on PC Neil Doyle and two of his colleagues in the early hours of Friday and have appealed for witnesses.
A 28-year-old man from Huyton has been arrested on suspicion of murder after handing himself in to a police station.
Detectives are reissuing their appeal for anyone who may have witnessed the assault of three men on Colquitt Street in Liverpool city centre in the early hours of Friday, 19 December, to contact them.
Police believe that three men were involved in the attack on PC Neil Doyle and two of his colleagues at about 3.15am and they are urging anyone who has any information to come forward.
A 28-year-old man from Huyton was arrested on suspicion of the murder of PC Doyle and two section 18 assaults, after he presented himself at a police station last night. He is being interviewed by detectives.
Anyone with information is urged to call the investigation team on 0800 230 0600 or Crimestoppers, anonymously, on 0800 555 111.
The brother of a teen who disappeared in 1979 has told ITV News he is "convinced" he was a victim of an alleged Westminster paedophile ring.Read the full story ›
A number of claims that police acted inappropriately in relation to child abuse allegations are being investigated, the Metropolitan Police said today.
Speaking at a press briefing today, Deputy Assistant Commissioner Steve Rodhouse said Professional Standards were looking into the claims, which cover a period from the 1970s up to 2005.
Some cover-up allegations are related to different strands of Operation Fairbank - a wide-ranging probe into alleged abuse - while others are completely unrelated, he said.
"We take any allegations of impropriety by police officers very seriously," Rodhouse said.
A total of 18 separate child abuse investigations are currently underway as part of the over-arching Operation Fairbank - a wide-ranging probe prompted by allegations of historical paedophilia made by MP Tom Watson.
Police say these 18 strands are "varied", not all linked and "not all in London", adding that some relate to care homes, and not all involve "VIPs".
One of these 18 is Operation Midland, which the force has been discussing today, and which will cover claims that three boys' deaths were linked to alleged abuse involving MPs in London.
One thousand people have been interviewed and 900 documents have been seized so far as part of the wide Fairbank investigation.
At present, five people have been charged over historical claims - including John Stingemore and Father Anthony McSweeney in relation to Grafton Close Children's Home in the capital.
However, they have so far received no allegations of abuse by any "VIPs" at Elm House Guest House in west London, and are appealing for anyone who may have been abused there to come forward.
Police investigating the alleged murders of three boys have confirmed they are checking against missing person files from the time, ITV News Correspondent Ronke Phillips reports.
Dets on alleged historic Westminster paedophile ring confirm they are going through missing person files from the time. @itvlondon
No bodies have been found at present to support the murder claims - which are said to be linked to an alleged Westminster paedophile ring.
However, police say they believe the allegations - - to be "credible and true" and are taking them very seriously.
Investigators believe Dolphin Square - a London housing estate close to the Houses of Parliament where many MPs have their homes - is an area of interest in a probe into an alleged Westminster child abuse ring and three related allegations of murder.
They are appealing for any boys who think they may have been victims or any residents who lived there and may have suspicions to come forward.
The historical allegations were made by a victim calling himself "Nick".
He alleges he was abused by a group of MPs and other high profile individuals between 1975 -84.
The information he has given them relates to the alleged murders of three young boys and police believe that it is "credible and true".