In the end, a magistrate's court verdict landed him right in the place he perhaps never thought he would end up in - jail.
Pardoned
However, he has been granted a new lease of life. President William Ruto pardoned him, giving him a breather to spend his remaining days on Earth as a free man.
But what led him to the wrong side of the law?
As a former Kemri boss, Koech was found guilty of fraudulent acquisition of public property and fined Sh19.6 million. The case was heard before Senior Principal Magistrate Victor Wakumile, who said if Koech is unable to pay the fine, he will serve a six-year jail term.
Koech was accused of transferring Sh19.3 million from Kemri's bank accounts to his personal accounts during his tenure as the Managing Director.
On August 16, 2006, some Sh800,000 was transferred from the corporation's account, another Sh6 million on December 5, and Sh12.5 million on December 13 of the same year.
Koech was accused of instructing the bank to transfer the funds. The money at the heart of the case was said to have been allocated to the Centre for Disease Control (CDC) in Kisumu.
In particular, the former Kemri boss faced three counts; accused of fraudulently acquiring Sh800,000 from Kemri on August 17, 2006, in Nairobi.
At the same time, he was charged with irregularly acquiring Sh6 million and an additional Sh12.5 million from the government's research agency on December 12, 2006.
He was also charged with an alternate count of using his position to access money meant for Vector Biological and Control Research (VBCR).
However, the professor asserted his innocence. He told the court that he had reimbursed the amount in 2015. Koech said he had paid an extra Sh3 million as interest.
He also said there was a mutual agreement with the EACC that it would no longer bother him with the fund's issue.
List of 37
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Koech is among 37 persons who were pardoned by the President.
Others are Burfa Jara Dokota, Ismael Kalamsho Kabiru, Mohammed Alango Durbu, Samuel Ndugi Ngugi, Ann Wangari Mungai, Robert Matekwa Machafu, Joseck Nyaribo Ngangicha, Ann Ngonyo, James Githui Wathiaka and Mary Wanjiku Nduta.
Also on the list are Abraham Musili Ngalukya, John Mwangi Gachogu , James Mbae Mutegi, David Maina Irungu, Linus Maina Wanyambura, Francis Mwenda, Julius Kangethe Mungai and Catherine Ngene Kakumbo.
Similarly, the President also pardoned Wafula Wamukota, Jane Chesigei Sang, Purity Wangu Muchoki, James Lopei Lotenel, Edward Maina Thuo, Julius Mbugua Nyiri, and Matthew Sigei.
Bonventure Mukhwana Mutali, Stephen Kilemi, John Kirunji M'Rimbere, Peter Kariuki Kihara, James Barasa, Douglas Thiongo Kibucha and Protus Simiyu Shikuku were also freed.
The list also included Joseph Ekitela Ekai, Gabriel Wanjenji Kuria, Joel Mburu and John Kimemia Waweru.
A trace by The Standard shows Jara, Kalamsho and Alango had been charged with murder. They were found guilty of killing Adow Dakane and were sentenced to death by Justice Jessie Lesiit.
They had tried twice to be resentenced. The first time was before Justice Luka Kimaru (now Court of Appeal Judge) while the second application was before Justice Daniel Ogembo.
Justice Kimaru, in a ruling on May 21, 2019, resentenced the trio to serve 10 years in jail.
What landed them in jail?
On October 28, 2007, the three were all travelling together with 10 other men and women in a matatu.
According to Justice Lesiit's judgment, the matatu was being driven by Abdi from Buka to Bangale. The passengers left Buka at 2pm and arrived at Bangale at 4pm.
The three witnesses said within 200m of Bangale town and Bangale Police Station, the vehicle came across huge rocks, tree trunks and tyres blocking the road.
Just before the vehicle came to a stop, a group of between 10 and 15 people emerged from nearby bushes, at a bend on the road.
They flagged down the vehicle. The court heard that as soon as the vehicle stopped, Mohamed Gamicha Gamo (deceased) was pulled out by Adow, who held him by his collar, with assistance from Jara, who held the deceased by his legs.
According to prosecution witnesses, Jara and Jara Dokota stabbed the deceased with Somali swords, each having their own weapon.
It was alleged that Alango, Kalamsho, and the others with them also attacked the deceased with swords, bows, and arrows.
Three witnesses in the case recounted to the court that they arrived at the Bangale Police Station together with other passengers from the matatu they were travelling in. They reported the incident to the police.
All of them denied being involved in the murder.
Kalamsho told the court that he was at home with his co-accused at the time of his arrest. He testified that all his co-accused were his neighbors.
Ann Wangari Mungai, who had been in prison since 2004, is also now a free person.
She had been convicted by Justice Alnashir Visram to suffer death over the murder of Danstun Wambugu Waithaka on September 18, 2004.
However, she sought to have her sentence, which had been commuted to life, reduced following the Supreme Court's verdict outlawing mandatory death sentences.
On October 20, 2020, Justice Mumbua Matheka reduced her sentence to 40 years, which was to be calculated from July 24, 2004, the date of her imprisonment.
Remorseful
She expressed remorse in her application for review. However, Justice Matheka noted that she still blamed her stepchildren for what happened.
"It would appear that in the 20 years she has been in prison she has not contemplated the magnitude of her actions; the fact that the child for whose murder she was found guilty was innocent and did not deserve to die.
"This, in my considered view, is not the attitude of a person who has taken responsibility for her actions. It is not the attitude of a person who has seen her own role in the loss of the child's life and I am not persuaded that a non-custodial sentence would be suitable for in her case," said Justice Matheka.
She was the last person seen with the deceased.
In the case, the prosecution's main witness was her husband James Waithaka, and the father of the deceased.
He gave evidence that Wangari was his second wife, whom he married in 1993. He had previously married his first wife in 1977, with whom he had four children, including the deceased, who was the youngest.
Waithaka said he had differences with his first wife, which led her to leave in 1995, but she did not take the children with her.
According to his testimony, there was animosity between Wangari, who had her own child, and his children from the first marriage.
According to Waithaka, the deceased had been treated with cruelty. He narrated several incidents that showed bad blood between the accused and the deceased.
On the material day, the deceased was sent out to graze the cow. He was seen returning with the cow at 5pm but was never seen again. It was not until the following day that his dead body was found by the father in a sack concealed in the kitchen store.
Several items were recovered, including the blood-stained skirt belonging to the accused, a broom, a jembe, a metal bar, and a rope, all of which were stained with blood.
Wangari denied killing him.