Dov Lior was pulled over while driving and arrested. While the reason for the arrest has not yet been made public, there has been a standing arrest warrant for Lior for months because he refused to answer a police summons for questioning about his role in the publication and distribution of Torat HaMelech, the racist and xenophobic book written by Chabad rabbis that calls for the murder of Arab babies that might one day grow up to hate Jews.
The Jerusalem Post's brief report provides no other details.
I'll update this post or post something new when more information is available.
Update 11:12 am – According to the Jerusalem Post, police held Lior for only an hour, asked him questions about the book, and then released him.
During this time 200 protesters blocked Highway 1 at the entrance to Jerusalem and another 20 demonstrated outside the police station.
The Post noted that:
Knesset members from the National Union were outraged over the arrest. Uri Ariel said on Monday afternoon that “hunting down rabbis who rule on matters of Jewish law is not the task of the police and State Attorney's Office.” Michael Ben Ari called for the dismissal of the public security minister, since police “treat Arab leaders with kid gloves, while here are disgracing a great rabbi.”
Others joined them in expressing their anger. Heads of the Land of Israel Caucus MK Zeev Elkin (Likud) and MK Arie Eldad expressed their “shock over the police's decision to employ detectives to arrest a rabbi in Israel, as though he were a common criminal, just because of his halachic stance.” The caucus called for the release of Lior and that the investigation be called off.