A second shooting in three days in South Korea has led to tightened regulations on gun ownership, South Korea’s police agency said Friday in a statement, according to the Associated Press. The new regulations would include strengthening the screening of those seeking a gun license and shortening the validity of those licenses.

The police said that the weapon used in Friday’s shooting was a shotgun and that the perpetrator had a proper license for the gun, which he retrieved 20 minutes before the shooting. In that instance, a 75-year-old man whose last name is Jeon shot two relatives and a policeman in Hwaseong, Gyeonggi province, near Seoul, before killing himself. The first policeman who arrived at the scene was shot on arrival by Jeon, according to the Korea Herald, and the daughter-in-law managed to flee the scene by jumping from the second floor of the crime scene. Jeon killed his brother, 86, and sister-in-law, 84, and the three were reported to be involved in a financial dispute, according to the Herald. The police said that the 86-year-old victim was wealthy and had some 10 billion Korean won ($9 million) in assets, according to the Korea Times.

Police later found a suicide note in Jeon’s car. “I have written everything down by the book. I am sure no one has found out about my plans,” the letter read, according to authorities. The police said that Jeon had frequently threatened his brother and family in the past when he got drunk, and added that Jeon was under the influence of alcohol during the shooting, according to the Herald.

Jeon's attack followed another shooting spree on Tuesday when a gunman opened fire at a convenience store in Sejong, central South Korea. Three people were killed, and the gunman killed himself after the attack. The gunman had retrieved two shotguns from a police station hours before the shooting, reports said.

South Korea has strict gun laws, but people are still allowed to own shotguns and air rifles, according to the AP. The guns must be stored at police stations, and owners can only use the hunting weapons during legal hunting periods. According to the National Police Agency, South Koreans legally owned about 160,000 guns as of January, a figure that included hunting weapons and self-defense tools such as gas-emitting guns.

Gun violence is extremely rare in South Korea due to its gun laws, but there has been a spate of shooting deaths among its military in recent years. A 22-year-old conscript sergeant from South Korea’s compulsory military service turned his weapon against his comrades in June last year, killing five and injuring seven others. He was captured after a failed suicide attempt and convicted of murder on Feb. 3. The sergeant’s shooting was the third case of a South Korean soldier turning on his fellow soldiers in a decade.