Students have been beaten, journalists kidnaped and Roman Catholic church leaders threatened as rightist terrorist attacks in Chile have increased significantly in recent weeks.

Informed sources here say they believe the violence may be related to the mid-July murder of Col. Roger Vergara, the director of the nation's military intelligence school who headed a recent investigation of one of the biggest tax-fraud scandals in Chile's history.

The $100-million scheme allegedly involved former agents of DINA, the dreaded secret police group that was disbanded in the late 1970s.

At first Vergara's murder was blamed on the Leftist Revolutionary Movement. But shortly after the killing, the head of the country's internal intelligence unit -- Gen. Odlanier Mena -- was removed from his post. Mena had a longstanding feud with his predecessor, Gen. Manuel Contreras, who was head of DINA until 1978 and is a close adviser of President Augusto Pinochet.

When he left his post July 24, Mena said he did not think the leftist group had killed Vergara. The murder "escaped the criteria of the [movement]," he said.

It was at this point that violent attacks against leftists and moderates began, leading observers to conclude that rightist extremists wanted to divert attention from the murder investigation.

One student died Saturday after being beaten, apparently by a group of rightist extremists known as the "Avengers of the Martyrs."

He was one of a dozen students who have been picked up on Santiago's streets and taken to secret "houses" for questioning by interrogators in street clothes who did not identify themselves. Several students were beaten. s

On Monday, various student groups denounced the recent terrorism and demanded the government crack down on those responsible "whatever their identity, motive or ideology."

The youth wing of the ad hoc human rights commission here issued a list of students it said have diappeared or have been arbitrarily detained in recent weeks.

At a mass for the slain student Monday, Episcopal vicar Christian Precht called for an end to terrorist attacks, which he said were growing out of control in Chile.

"There is still time to end this violence," he said, calling on the government to listen to the clergy when they denounced human rights violations, torture and other forms of institutionalized violence.

In the last several weeks, there have been a number of terrorist acts against the Roman Catholic Church here.

Last week, a Belgian-born priest who has lived in Chile for 13 years and is active in the church's human rights campaign was kidnaped by unknown armed civilians. He was released unharmed, but the government then ordered his expulsion. Officials refused to give church authorities any reason for the order.

The priest took refuge inside the home of Cardinal Raul Silva Henriquez, who has refused to turn him over to military authorities.

Last week two journalists -- one of whom is the public affairs director for the Catholic archdiocese -- were kidnaped and held for nine hours. They were questioned about the Vergara murder and alleged leftist connections.

Other attacks against the church have included death threats against the clergy -- including the cardinal -- and the placement of bombs near church facilities.

Meanwhile, the investigators of the Vergara killing and the tax-fraud scandal continue. Last week Hoy magazine, one of the most outspoken critics of the Pinochet government, published information linking DINA agents with the scheme, which Chileans call the "fraud of the century."

The scandal allegedly also involves a number of foreigners, possibly Americans, who were going to work through an imaginary corporation called the Union Trading Co.