In an interview with investigative TV show Uvda on Wednesday, the police chief charged that "powerful" elements had tried to collect information about police officers investigating the prime minister.
"People are being murdered here, the police should handle that," Lieberman said in an interview with Kol BaRama Radio.
"I was sorry to see this entire spectacle, the exchange of blows in the media," he added. "Each person needs to do what he has been tasked with, without a lot of PR."
He went on to stress that "Any person is innocent unless proven otherwise; the presumption of innocence applies to all. The only body authorized to determine whether a person is guilty or innocent is the court. The rest of it is just needless politics."
The defense minister declared he would not quit the government even if Attorney General Avichai Mandelblit decides to indict Netanyahu. "Only after a court conviction," he stressed.
"Experience is the best teacher, I say this as someone who was unanimously acquitted," Lieberman added. He resigned as foreign minister in December 2012 after he was charged with breach of trust and fraud. He was eventually acquitted, allowing him to return to the Foreign Ministry in November 2013.
He said the prime minister "is functioning excellently despite the investigations" against him.
Lieberman refused to address Alsheikh's claims, saying "I think all of this is completely unnecessary. I think the less talk and the less preconceived notions right now, the healthier."
"I propose everyone calm down and wait," he continued. "There's still a long process ahead."
Earlier Thursday, Netanyahu took to Facebook for the second time in 24 hours to attack the police chief. "How would you feel if the police investigators conducting an investigation against you claimed that you had employed private investigators against them and against their families?" the prime minister wrote.
"Can investigators who think the interrogatee is following them, or sending a woman to file a sexual harassment complaint against the head of their unit, do their job in an unbiased manner?" the prime minister asked, referring to Lahav 433 head Roni Rittman, who resigned amid sexual misconduct allegations. "And what does this say about their recommendations?"