The deadly storming of a police station by a little-known Armenian political grouping has sparked a tense drama in Yerevan, as the gunmen demand the release of their jailed leader in exchange for police officers they are holding hostage.

When more than a dozen gunmen attacked the Erebuni police station on July 17, they killed one officer, reportedly a police colonel, and wounded six other people. The crisis then moved into protracted negotiations, and three of the seven hostages were freed on July 18.

But why are the gunmen demanding the release of the head of Armenia's Founding Parliament party, Zhirayr Sefilian, and calling on Armenians to take to the streets to overthrow the government? Here are four things you need to know about Sefilian and his group:

Who is Zhirayr Sefilian?

Sefilian, 49, is little-known outside of Armenia, but he is a prominent figure within the country thanks to his role in the 1988-94 conflict between Azerbaijan and Armenia over Nagorno-Karabakh.

A Lebanese-Armenian by birth, he gained military experience fighting in an Armenian quarter of Beirut during Lebanon's 1975-90 civil war before moving to Armenia with his family in 1990. During the Nagorno-Karabakh war, in which Yerevan backed separatists seeking independence from Baku, Sefilian commanded a unit of fighters that wrested the city of Shusha from Azerbaijani forces in 1992, scoring one of the first significant military victories for the Armenian side in the conflict.

Since then, Sefilian has used his war-hero status to gain an audience for his belief that Armenia is plagued by inept leadership and corruption and in need of urgent rescue.

He initially entered the political arena by mobilizing other Nagorno-Karabakh war veterans and voicing their complaints over poor housing, health care, and unemployment.

He then sought to widen his support base by launching Founding Parliament along with several like-minded public figures from a variety of backgrounds.

But the party is unique in that it deliberately remains outside of the current political system.

"They refuse [to participate in] the election process as it is today in Armenia due to violence and non-transparency in the system, and their program is that this government should resign and we should have a transition government and new elections," says Haykak Arshamyan, a political analyst at the Regional Studies Center in Yerevan. "Their ideas are a bit complicated and unclear."

Members of the group are believed to number in the thousands and many seem to see themselves as self-appointed guardians of society. The hostage takers have described themselves as the Daredevils of Sasoon, in reference to an Armenian epic tale from the Middle Ages about a generation of men fighting for Armenian independence.

Why storm a police station?

The assault closely follows the arrest of Sefilian and six other members of Founding Parliament on June 20 on suspicion of acquiring weapons and planning to seize government buildings in the capital, Yerevan. The arrests came after traffic police discovered that the driver of a car involved in an accident was carrying weapons and the driver pinned the weapons on Sefilian. When Sefilian appeared in court, he was formally charged with acquiring and possessing weapons, but the allegations of plotting a coup were dropped.

However, the arrest of Sefilian, who has been imprisoned twice before -- in 2007 and 2015 on charges of illegally possessing weapons and organizing mass disturbances -- may not have been the only spark for the current crisis.

WATCH: Armed Attackers Storm Yerevan Police Headquarters

Tensions are also running high among Armenian nationalists over purported leaks to the Russian press suggesting that the Kremlin is pressing Yerevan to trade land for peace in a new peace initiative. The leaks, reportedly from Kremlin officials, say that Moscow wants the Armenians to progressively give up land that they seized during the war around Nagorno Karabakh proper in exchange for international recognition of the self-declared government of the territory. The government of Armenian President Serzh Sarkisian says it has received no such proposal from Moscow, but the disclaimer has done little to calm former Armenian fighters' fears that they could lose some of the land they gained.

How is Founding Parliament viewed by mainstream opposition groups?

As a fierce critic of the government, some of Sefilian's views resonate with more mainstream opposition parties, though they distance themselves from his radicalism.

One indication of the mixed feelings about Sefilian is the key role of one prominent mainstream opposition figure in the negotiations to end the hostage crisis. Nikol Pashinian, head of the Civil Contract party, says he has intervened in an effort to avoid more bloodshed, but he also says the ruling party shares some of the blame for the action because of the "overall atmosphere of injustice in the country."

Another opposition party, the Heritage Party, has also said the government shares some responsibility. Armenia's main opposition party, the Armenian National Congress, has issued a statement saying it is against violence and hopes the situation will be resolved soon.

The mixed opinions about Sefilian in Armenia are mirrored in Nagorno-Karabakh, where he is hailed as a war hero but a dubious political ally. The administration of Nagorno-Karabakh, which follows a security strategy of staying as close to the powerful in Yerevan as possible, in January 2015 refused Sefilian entry into the territory. Sefilian, who was leading a 30-car convoy to hold political rallies, was confronted by police upon entering Nagorno-Karabakh and more than two dozen people, including Sefilian, were injured. The reasons for the confrontation have never been made clear, as a police investigation into it continues.

Where does the crisis go from here?

For now, Sefilian and his movement remain marginal players in Armenia. But the resolution of the hostage crisis could determine whether they remain so or become a rallying point for wider public dissatisfaction with the government.

The gunman have already killed one police officer. But Arshamyan says that, if the gunmen murder any hostages -- who include a deputy national police chief and a deputy head of the Yerevan police department, the action could tar the image of Armenia's opposition parties in general while rallying support for the government.

If the situation ends in such a way that any brutality is perceived as being carried out by the police, he says, and the gunmen can be seen as martyrs, the incident could instead help to consolidate political opposition groups against the ruling party.

Armenia is due to hold parliamentary elections next year as the country moves from a presidential system to a parliamentary system.

Yerevan bureau Editor In Chief Siranuysh Gevorgyan contributed to this report

