Check out http://www.jewish-funeral-guide.com/tradition/rending.htm

Also, find a dictionary or encyclopedia of theology and search for "rending garments" as a mourning tradition.

One book on Amazon: Code of Hebrew Law - Shulhan 'Aruk - Yoreh De'ah (treating of the laws of visiting the sick; laws of rending garments; laws of aninuth and laws of mourning), The Jurisprudence Press 1954

by Chaim N. Denbur

There are several ways to approach this subject

firstly - do a word search of all Hebrew bible (Old Testament) for instances when clothes were torn as a sign of mourning - analyze similarities between the instances and differences

-look up commentaries on the particular books and read up what is being said about the action

-also search on JStor - found this article that you can start with

The Tearing of Garments as a Symbol of Mourning, with Especial Reference to the Customs of the Ancient HebrewsFree content

Morris Jastrow, Jr.

Journal of the American Oriental Society, Vol. 21, Index to the Journal of the American Oriental Society, Vols. 1-20 (1900), pp. 23-39

[Journal]

http://www.jstor.org/action/doBasicSearch?Query=tearing+of+clothes+mourning&acc=on&wc=on&fc=off&group=none

Do not neglect the Encyclopedia of Judaism, which includes articles on the "Old Testament."

There are examples of this practice of tearing clothes in the biblical texts, and it may be worthwhile to look into it. Still, the main point seems in my view to be the situations, that make this practice significant. Within canon we find a number of texts that vividly express human despair - even before God. It seems to boil down to an awareness of trust in God, as in the case of Psalm 80 and other places. Here it is more like a tearing expressed verbally and emotionally as a challenge and call for God's intervention. This motif of lament and despair may be one of those expressed by ritual garment-tearing, but there may clearly be other motifs.

As a survivor of my Mothers traumatic death, I was asked to be a speaker for a bereavement course and to integrate some of the things I had learned through my grief journey with a group psychology students. During this time, I integrated some of my insights from having been a researcher on a suicide / traumatic death study as well as my insights from a Christian faith perspective that aided in my journey. I am uploading you a document I created for myself  which outlines some of the scriptures that relate to the ritual of tearing / rendering clothes as an expression of grief in the Old Testament as well as a New Testament perspective (taken from a pastoral website) of the temple veil being rended as an expression of Gods grief after the death of Yeshua (Jesus).  I hope this gives you some place to start in understanding the ritual of rending clothes as an expression of grief. The insights certainly helped me on many levels and I do believe that such traditions and practices are helpful for the mourning process.

https://www.forewordreviews.com/reviews/rending-the-garment-review.pdf

See Zlotnik Guide to Mourning

I find this article very helpful: Eileen F. de Ward, “Mourning Customs in 1, 2 Samuel”, Journal of Jewish Studies vol. 23 no. 1 (1972) 1-27. The third part of this article beginning from page 8 focuses on Tearing Clothes as a sign of mourning in the Old Testament. Although the author concentrates on 1-2 Samuel, the points discussed are useful in understanding other parts of the Old Testament. 

This is a very useful article: W. Thiel, “qāra‘”,Theological Dictionary of the Old Testament  vol. 13 (Grand Rapids, Michigan: Eerdmans, 2004) 175-180. 

https://www.researchgate.net/publication/305887180_Beyond_the_Border_Yellow_Goes_International

Article Beyond the Border: Yellow Goes International

The tearing of clothes was something that Jews practiced in the old testament to indicate remorse, sorrow and repentance.  But today we tear our hearts instead of our clothes to follow the same pattern.