According to the Bangkok Post, the incident took place at a wedding in Nakhon Ratchasima, Thailand.
At the wedding, 29-year-old groom Chaturong Suksuk shot and killed 44-year-old bride Kanchana Pachunthuek, the bride's mother and sister and one person with a gun he took from his car for an undetermined reason.
Chaturong and Kanchana had lived together for three years before they married, according to Thai media.
Chaturong had clinched a silver medal in swimming at the Asean Para Games in Indonesia last year. He was also believed to be on the list of athletes competing in the World Abilitysport Games in Thailand next month.
The groom, who seriously injured another person, later committed suicide with the same gun.
The investigation into the cause of the incident is ongoing.
