Article: On the next day, December 18, protests turned into civil unrest as clashes between troops, volunteers, militia units, and Kazakh students turned into a wide-scale confrontation. The clashes could only be controlled on the third day. The Almaty events were followed by smaller protests and demonstrations in Shymkent, Pavlodar, Karaganda, and Taldykorgan. Reports from Kazakh SSR authorities estimated that the riots drew 3,000 people. Other estimates are of at least 30,000 to 40,000 protestors with 5,000 arrested and jailed, and an unknown number of casualties. Jeltoqsan leaders say over 60,000 Kazakhs participated in the protests. According to the Kazakh SSR government, there were two deaths during the riots, including a volunteer police worker and a student. Both of them had died due to blows to the head. About 100 others were detained and several others were sentenced to terms in labor camps. Sources cited by the Library of Congress claimed that at least 200 people died or were summarily executed soon thereafter; some accounts estimate casualties at more than 1,000. The writer Mukhtar Shakhanov claimed that a KGB officer testified that 168 protesters were killed, but that figure remains unconfirmed.

Now answer this question: How did the Kazakh SSR government say the two protesters were killed?
blows to the head