Some even say the blast was the result of infighting between different parts of Russia's security agencies.
If you look at some of the statements above, the perpetrators have not yet been identified, but from these statements it is possible that this was an act of terrorism carried out by a group of terrorists, but it does not rule out the possibility that Ukraine intervened in this case.
russian response
Russian President Vladimir Putin has signed a decree instructing security on the Crimea bridge to be tightened after an explosion destroyed parts of this infrastructure on Saturday. Putin also ordered the formation of a special committee to investigate this incident
The bridge is a major artery for Russian forces that control much of the Kherson region in southern Ukraine and for the Russian naval port of Sevastopol, whose governor told locals "Keep calm." Don't panic. Russia's governor for Crimea Sergei Aksyonov said the damage was "not fatal". He previously said Crimea had one month's fuel and two months' food. (CNN INDONESIA, 2022)
References
Adams, P. (2022, Oktober 10). Perang Ukraina: Siapa dan apa yang menyebabkan ledakan di jembatan Krimea? Retrieved from BBC News Indonesia: https://www.bbc.com/indonesia/articles/c72j9y3eq31o
CNN INDONESIA. (2022, Oktober 9). Putin Perintahkan Keamanan Jembatan Crimea Diperketat Usai Ledakan. Retrieved from www.cnnindonesia.com: https://www.cnnindonesia.com/internasional/20221009044428-134-858125/putin-perintahkan-keamanan-jembatan-crimea-diperketat-usai-ledakan
CNN INDONESIA. (2022, juni 16). Tentang Jembatan Terpanjang di Eropa yang Akan Dihancurkan Ukraina. Retrieved from WWW. cnnindonesia.com: https://www.cnnindonesia.com/internasional/20220616191036-134-809934/tentang-jembatan-terpanjang-di-eropa-yang-akan-dihancurkan-ukraina/2
SINDONEWS. (2022, OCTOBER 16). Sejarah Pembuatan Jembatan Crimea, Jembatan yang Dibom Ukraina Baru-baru Ini. Retrieved from WWW.SINDONEWS.COM: https://international.sindonews.com/read/914325/41/sejarah-pembuatan-jembatan-crimea-jembatan-yang-dibom-ukraina-baru-baru-ini-1665929447
Wibawana, W. A. (2022, Oktober 9). Jembatan Crimea Meledak Tewaskan 3 Orang, Ini 5 Hal yang Diketahui. Retrieved from Detik News: https://news.detik.com/internasional/d-6337680/jembatan-crimea-meledak-tewaskan-3-orang-ini-5-hal-yang-diketahui