In a letter from a small jail cell in Cairo, two Canadian men who were swept up in the security crackdown by Egypt’s military-led government last month describe the brutal and “ridiculous conditions” in which they have been held without charge for six weeks.

The men, Dr. Tarek Loubani and John Greyson, were arrested during clashes in Cairo on Aug. 16, when they stopped to ask police officers for directions to their hotel after the 7 p.m. curfew. As my colleague Liam Stack reported, they were passing through Egypt on their way to the Gaza Strip, where Mr. Loubani, a professor of emergency medicine at Western University in London, Ontario, intended to provide training to Palestinian doctors as part of a humanitarian mission. Mr. Greyson, a professor at York University in Toronto and a well-known filmmaker, was documenting the trip to Gaza.

They have been detained without charges since then, but an Egyptian foreign ministry spokesman told The Toronto Star on Friday that they would soon be charged, citing what he described as evidence on a memory stick that showed they had recorded some of the crackdown.

Here is the complete text of the letter written by Dr. Loubani and Mr. Greyson from Tora Prison outside Cairo, released by relatives and friends campaigning for their release.

We are on the 12th day of our hunger strike at Tora, Cairo’s main prison, located on the banks of the Nile. We’ve been held here since Aug. 16 in ridiculous conditions: no phone calls, little to no exercise, sharing a 3m x 10m cell with 36 other political prisoners, sleeping like sardines on concrete with the cockroaches; sharing a single tap of earthy Nile water. We never planned to stay in Egypt longer than overnight. We arrived in Cairo on the 15th with transit visas and all the necessary paperwork to proceed to our destination: Gaza. Tarek volunteers at al-Shifa Hospital in Gaza, and brings people with him each time. John intended to shoot a short film about Tarek’s work. Because of the coup, the official Rafah border was opening and closing randomly, and we were stuck in Cairo for the day. We were carrying portable camera gear (one light, one microphone, John’s HD Canon, two Go-Pros) and gear for the hospital (routers for a much-needed Wifi network and two disassembled toy-sized helicopters for testing the transportation of medical samples). Because of the protests in Ramses Square and around the country on the 16th, our car couldn’t proceed to Gaza. We decided to check out the Square, five blocks from our hotel, carrying our passports and John’s HD camera. The protest was just starting — peaceful chanting, the faint odour of tear gas, a helicopter lazily circling overhead — when suddenly calls of “doctor.” A young man carried by others from God-knows-where, bleeding from a bullet wound. Tarek snapped into doctor mode and started to work doing emergency response, trying to save lives, while John did video documentation, shooting a record of the carnage that was unfolding. The wounded and dying never stopped coming. Between us, we saw over fifty Egyptians die: students, workers, professionals, professors, all shapes, all ages, unarmed. We later learned the body count for the day was 102. We left in the evening when it was safe, trying to get back to our hotel on the Nile. We stopped for ice cream. We couldn’t find a way through the police cordon though, and finally asked for help at a check point. That’s when we were: arrested, searched, caged, questioned, interrogated, videotaped with a ‘Syrian terrorist,’ slapped, beaten, ridiculed, hot-boxed, refused phone calls, stripped, shaved bald, accused of being foreign mercenaries. Was it our Canadian passports, or the footage of Tarek performing C.P.R., or our ice cream wrappers that set them off? They screamed ‘Canadian’ as they kicked and hit us. John had a precisely etched bootprint bruise on his back for a week. We were two of 602 people arrested that night, all 602 potentially facing the same grab-bag of ludicrous charges: arson, conspiracy, terrorism, possession of weapons, firearms, explosives, attacking a police station. The arrest stories of our Egyptian cellmates are remarkably similar to ours: Egyptians who were picked up on dark streets after the protest, by thugs or cops, blocks or miles from the police station that is the alleged site of our alleged crimes. We’ve been here in Tora prison for six weeks, and are now in a new cell (3.5m x 5.5m) that we share with ‘only’ six others. We’re still sleeping on concrete with the cockroaches, and still share a single tap of Nile water, but now we get (almost) daily exercise and showers. Still no phone calls. The prosecutor won’t say if there’s some outstanding issue that’s holding things up. The routers, the film equipment, or the footage of Tarek treating bullet wounds through that long bloody afternoon? Indeed, we would welcome our day in a real court with the real evidence, because then this footage would provide us with our alibi and serve as a witness to the massacre. We deserve due process, not cockroaches on concrete. We demand to be released. Peace, John & Tarek

Mohammed Loubani, the detained doctor’s brother, explained in an e-mail to reporters that supporters of the two men had initially withheld their letter from jail, hoping that they would eventually be released. That changed after the report that the two men might now be charged.

“If the Egyptian government wants to claim that Tarek and John are being held in accordance with a free and fair judicial process,” Mr. Loubani wrote, “they will have to address why Tarek and John were beaten by Egyptian police after being arrested — their bruises were documented by Canadian consular staff who urged us to keep quiet — and why providing medical aid to critically injured Egyptians is a grounds for their detention.”