Landslides in the Indian Himalayan region occur at a significantly higher rate than the global average, posing a severe threat to the economy and the lives of people. Rainfall has been a major contributing factor to the occurrence of these landslides. This study presents a forensic stability analysis of a landslide in the Paglajhora region of Darjeeling, West Bengal, which was caused by a heavy rainfall event during the monsoon season. A transient fully coupled analysis is conducted in RS2 software to examine the stability of a critical slope section (which includes a road bench of NH-55) that failed due to heavy rainfall. Additionally, a suitable remedial measure is suggested to enhance the structural stability of the original slope, which includes using anchored sheet piles in combination with granular backfill. The analysis results indicate that a heavy rainfall event lasting 31 days (about 1 month) triggered the landslide in the Paglajhora region. The infiltration of rainwater increased pore water pressure (PWP) raising the phreatic surface level near the road bench, which led to the subsidence of underlying soil mass. The implementation of anchored sheet piles is found to significantly improve the stability of slope around road bench area. Furthermore, the granular backfill behind the sheet piles efficiently facilitates rainwater drainage, leading to decreased PWP and consequently lowering the phreatic surface near the road bench. In summary, the current study highlights that using anchored sheet piles with an effective drainage system can mitigate the risk of rainfall-induced landslides in the region under investigation.