Police sources said the arrest was made after a suspected killer confessed before a magistrate that Mohiuddin was directly involved in the murder.

Jahangir, one of the arrested suspects, in the confession said Prof Mohiuddin masterminded the killing to remove impediment to his promotion.

Mohiuddin was present during the murder along with his student and RU unit Islami Chhatra Shibir President Mahbub Alam Salehin, he added.

Rajshahi Metropolitan Police (RMP) Commissioner Nayeem Ahmed confirmed the arrest, which was made within the power of police provided by the law of the land.

"We have still a lot of things to do to complete the investigation," he said when asked if other teachers or beneficiaries are involved.

RMP Deputy Commissioner (East) Lokman Hakim explained all procedures including taking permissions from the head of the state and the home ministry for the arrest.

"Jahangir's confession under the section 164 was enough for arresting Prof Mohiuddin," said Lokman. He however did not elaborate on the confession for the sake of investigation.

The police had earlier kept watch on Mohiuddin's movement and his house since the arrest of Jahangir.

They mounted the watch yesterday morning and a number of plainclothes policemen were seen following Mohiuddin.

In the evening, several platoons of police from four police stations and RMP reserve forces laid siege around the campus. A team of eight policemen led by the Detective Branch assistant commissioner went to Mohiuddin's house and asked him to go with them around 6:00pm. They took Mohiuddin in a microbus to the RMP headquarters.

The RMP commissioner supervised the entire operation and held a closed-door meeting at his office to design the raid.

Earlier in the day, the police also recovered the missing travel bag and cellphone of Taher following the statement of Jahangir's brother Abdus Salam.

Police raided their cousin's house at Kadirganj and found the travel bag. They also recovered Taher's cellphone from Jahangir's house.

JAHANGIR'S CONFESSION
Metropolitan Magistrate Zobeda Khatun recorded Jahangir's confession before the arrest of Mohiuddin.

Jahangir said he along with his brother Salam, relative Nazmul committed the murder in presence of Mohiuddin and Salehin.

He said Mohiuddin asked him several months ago if he would kill Taher, who used to live alone after his family shifted to Dhaka.

He claimed Mohiuddin went to Taher's house during his absence and masterminded the murder, offering Jahangir money and a computer and Salam and Nazmul jobs at RU.

After the murder was committed, Mohiuddin and Salehin asked them to dump the body into a sewer, he added.

MOHIUDDIN'S PROFILE
Mohiuddin, a resident of Faridpur, joined the RU as a lecturer in 1990 and went to Belgium for higher education in 1992.

He did his PhD from Japan's Tsukuba University in 1997 and was made assistant professor in 1998. He went to Japan again for a postdoctoral degree on geological survey.

He was a visiting professor of Tsukuba University for two years since 2001.

He applied for the post of professor in March last year and was denied repeatedly for lack of random 12 years in service, quality publications and expert opinions in favour of him.

TAHER, ONLY BARRIER
RU sources said Prof Taher was the only impediment to the promotion of Mohiuddin, who might have orchestrated the murder to remove the obstacle.

He being the senior most teacher with a considerable influence on his colleagues, most of who were his students, disagreed many times with Mohiuddin's application for the post of a professor.