Post-it note with handwritten message in blue marker. The message reads: "I think this means when there is hate and sorrow be the one who makes happiness and kindness into the world. Simon [last name redacted]."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Post-it note with handwritten message in green marker. The message reads: "Live for those we have lost. Be well. Love from Boston MA."

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter reads: "To our esteemed sisters and brothers I offer sorrow in your losses, comfort to enter into your memories and many blessings for your bright future as a synagogue to overcome. With all my love- Russell [last name redacted]."

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside contains a prayer and wishes for love and faith in God. The church's contact information is included on the back of the envelope.

Envelope containing letters written by members of the Point Loma Community Presbyterian Church in San Diego, California. The envelope is labeled with a piece of paper reading: "Letters for Tree of Life Synagogue."

Handwritten note signed by Ben and Beth of Toronto. Written in black ink on the back of stationary with the logo of Marriott Hotels. Staining due to exposure to the elements at the Wilkins memorial.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside contains words of prayer and encouragement. The church's contact information is included on the back of the envelope.

Laminated text of the Catholic "Beatitudes" blessing printed on paper with light blue checkered pattern in background. A yellow band with the words "The Beatitudes" appears in the upper center; blue and purple clouds covering the sun appear to the left. A handmade paper medallion with five decoratively rolled spirals and a silver string has been taped to the front.

Card from the Friendship Circle of Illinois. The front of the card features an illustration of 770 Eastern Parkway in Brooklyn, Ny., the international headquarters of the Chabad-Lubavitch movement. The inside reads: "To the Jewish community of Pittsburgh sheyichyu (may they live), I'm very sad to hear about the tragic passing of the eleven yidden (Jews) who were so brutally murdered al kiddush Hashem (sanctified by God). I hope there will be no more bad things that happen.

Rectangle-shaped card from a student at Fountain Valley School in Colorado Springs, Co. Card reads: "Dear members of Tree of Life synagogue. I am an international student from China. I am sorry for your loss and will stand with you. May peace with you and stay stong. Shalom. Warmly, Xiao Chao [last name redacted]." Small Star of David in lower right.

Printed note in black ink on bright green paper. The note reads: "Hate has no home here. Our hearts are heavy with grief." Tape marks visible on the right and left sides of the note. Color bleeding due to exposure to the elements at the Wilkins memorial.

Card addressed to David Rosenthal. Cover features a reproduction of a painting by Frank Crosby, a resident of the Emmaus Community of Pittsburgh. The inside contains messages of love and support written by other members of the Emmaus Community.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Floral tag from floral arrangement, which reads: "May the lord Be with you!" The message is written in black ink on a printed tag with white and purple flecked flowers.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The front cover reads: "Letters." The inside reads: "To Tree of Life family: Who can explain such an event? And how do we move forward? My prayer is that your faith in your God will see you through this grieving time and heal you all with His Grace. Steve [last name redacted]."

Rectangular piece of plywood wrapped in metal with embossed design of Hebrew word "Chai," meaning "Life."