What are the original beliefs of St. Thomas Christians on the nature of God and Jesus?

I looked at the [*Wikipedia* page on the St. Thomas Christians](https://en.wikipedia.org/wiki/Saint_Thomas_Christians) , the oldest school of Indian Christians who follow the teachings of St. Thomas the Apostle, who had travelled to India to preach. However, I couldn’t find what their beliefs *were* from that page. Were they Trinitarian or Unitarian? Are there any academic references (books, papers) that discuss their religious beliefs on the nature of God, Jesus, etc?