A 52-year-old man has been arrested for threatening and violent phone calls, emails and letters received by Labor deputy Angela Rayner.
He was arrested at an address in Halifax, West Yorkshire, on Wednesday morning, Greater Manchester Police said.
Detective Christopher Dean said: “Offensive, threatening or bullying behavior towards anyone is completely unacceptable and we will always do what we can to ensure that those responsible are identified and held accountable for their behavior.
“Although we have arrested a man, our investigation is still very ongoing and we will continue to pursue all available lines of investigation to identify all those responsible.”
Ms. Rayner reported that she had received the threatening contacts within a number of weeks.
A spokeswoman for Ms Rayner said: “Angela and her staff have received a number of threatening, malicious and insulting communications in recent weeks.
“We are working with the police to ensure that the perpetrators of these crimes are brought to justice and Angela would like to thank the police for their work during these investigations.
“Abuse and threats of this kind have an impact not only on Angela, but also on her family, her children and her staff, who are on the receiving end of this communication.
“Angela is currently on mourning leave after losing a loved one and she looks forward to being back at work as soon as possible.”
The arrest was directly related to a series of violent phone calls that the MP for Ashton-under-Lyme received on October 15, and the person has been released pending further investigations.
It comes at a time of increased focus on the safety of MPs and the abuse they receive in the wake of the assassination of Sir David Amess.
The Conservative MP for Southend West was fatally stabbed in a suspected terrorist attack when he held a constituency operation in Leigh-on-Sea, Essex earlier this month.