This package is an implementation of the STKDE function described in Nakaya and Yano (2010).
You can install stkde from github with:
# install.packages("devtools")
devtools::install_github("karpfen/stkde")
devtools::install_github("karpfen/stkde")
Nakaya, Tomoki, and Keiji Yano. 2010. “Visualising Crime Clusters in a Space-Time Cube: An Exploratory Data-Analysis Approach Using Space-Time Kernel Density Estimation and Scan Statistics.” Transactions in GIS 14 (3). Wiley Online Library: 223–39.